In the Bitcoin data directory, which is either C:\Documents and Settings\USERNAME\Application Data\Bitcoin\ or C:\Users\USERNAME\Appdata\Roaming\Bitcoin\ depending on what version of Windows you were using (replace USERNAME with your actual user name). Copy this folder onto your new Windows installation, install Bitcoin, and when you run it, everything should be exactly as you left it.

The wallet itself is in the file wallet.dat, and this is the only file that you absolutely need to back up (put simply, if you lose this file, you lose your money). That folder also contains your configuration settings and the blockchain database, which are important, but can easily be recreated if necessary, unlike your wallet.

Say there are two people who each want to buy a bitcoin, and one is willing to pay $220 and the other is only willing to pay $200, and you want to sell a bitcoin. Obviously, you'll sell it to the guy offering the highest price, so you sell it for $220. Now, the next person who wants to sell a bitcoin will only be able to get $200 for it, since the guy who bought yours for $220 isn't interested in buying another one. In this way, you selling your bitcoin has lowered the price from $220 to $200. Exactly the opposite happens when people want to buy. Obviously, it gets more complicated when there are many people all buying and selling bitcoins in different quantities for different prices, but it's the same basic principle.

Settings -> Options -> Network -> Connect through SOCKS proxy. The default proxy settings are for a standard Tor installation; you only need to change them if your Tor setup is non-standard.

Note that Tor only hides your IP address. It does nothing to prevent your transactions from being traced, which is more important. For more details, see en.bitcoin.it/wiki/Anonymity.

10 cents is too high? Well, you're always welcome to go with one of the cheaper money transmitters. Oh wait, you can't! There aren't any! Bitcoin's the cheapest there is. Now quit complaining and pay your fees.

A 51% has nothing to do with the amount of bitcoins one owns, only the amount of computing power one controls.

Well, there's your problem. Check your firewall settings. Perhaps your friend didn't approve of the amount of bandwidth it was consuming and decided to block it? That seems like the most likely explanation. Once you've sorted the connection problem, it will resume synchronisation as normal. And don't forget to encrypt your wallet - if you don't, anyone with access to your computer can steal your money. Do this immediately if you haven't already done so. Then back up your wallet after it's encrypted and keep the backup in a safe place.

Actually, it would be obvious not because of the collaboration required, but because all the pools that are not in on it will notice their blocks are being ignored. It will be noticed pretty much instantly, and once the miners of the attacking pool realise their pool is performing a 51% attack, they'll leave en masse for other pools, as almost all miners are either in it for the money or for the benefit of the network, and neither group wants any part of 51% attack (the first group doesn't want the massive price drop that a 51% attack is likely to cause, and the second group doesn't want a 51% attack simply as a matter of principle). When they leave, the attacking pool no longer has 51% and the attack is over, hopefully before they were able to cause any real damage.

Yes. So what? If I make something myself, I save others the effort of making it for me. But if someone else can do a better job of making it, it makes more sense for me to pay them to do it so I'm not wasting my time. Money allows us to concentrate on doing what we're good at doing and get other people to do what they're good at doing.

It helps price discovery. Anyone who ever buys or sells anything benefits from this.

Labour is outsourced when people in another country can do a better job for the same price, or the same job for a better price. This allows people in your own country to import better quality products, or the same products for less cost. And just what's so special about jobs in your own country, anyway? People in other countries need jobs too, you know. Are they somehow less deserving of a job than people in your country?

I never bet. Gambling is for losers. I am not biased about anything I invest in. I make decisions based on the best available evidence. Any investor who allows emotions to get the better of them is very likely to lose a lot of money very quickly. So I try not to let that happen. And so does anyone else who wants to make money.

You've got it backwards. Politics drives market manipulation, not the other way around. Markets themselves are pure. If you have something I want, and I have something you want, we make a trade and we both leave happy. The various markets are simply millions of people engaging in such trades on a global scale.

If she didn't have to pay money for the treatment, where would it come from? Who would spend years researching the treatment if they weren't going to get paid? Who's going to manufacture it? Who's going to administer it? As much as doctors and scientists enjoy working for the benefit of humanity, they still have to eat. Fact is, if she didn't have to pay money for the treatment she wouldn't have any treatment at all.

Pay close attention, because I'm only going to say this once more: people don't die because of a lack of money, they die because of a lack of stuff. There is only so much stuff in the world to hand out to people who need it. Clearly, we need some of system to decide who deserves to have this stuff and who doesn't. Money is that system. You acquire money by producing stuff that people want or need, and retain money by not consuming stuff that other people want or need. In other words, by being helpful and not being a burden on society. There are basically three kinds of people in the world who don't have enough money:
1) Those who are too lazy to work hard. Do these people really deserve to have stuff handed to them?
2) Those who work hard, but then squander their earnings. By spending their money on stuff they don't need, there is now less stuff remaining for people who do need it.
3) Those who, through no fault of their own, are unable to work, or have worked but have had their earnings stolen from them. These people are arguably the most screwed over by the system, but it is important to realise that money didn't create their problem: they'd be equally unfortunate whether money existed or not. Their lack of money is a symptom of their misfortune, not the cause. Life is just unfair, and money can't change that. But it does make life better for most people.

You're the one who's deluded. Money isn't wealth. Money is an abstraction of wealth which a person created for somebody else. Take me for example. My first job was in manufacturing. I created things. Things that other people want, and therefore are willing to pay for. That's how I made money: by creating things for other people. Then, when I was working in IT, I provided a service. A service that other people value. I got paid to do things for other people. Can you see a pattern forming? Every cent of every dollar I ever earned, I earned by helping other people. And if I were to spend that money on things for myself, that would reduce the amount of things remaining for other people, since there's only a finite amount of stuff in the world. But by "hoarding" my money, that stuff is available for other people who need it more than I do. By working for money and not spending it, I am helping people and then not taking anything from them. If only everyone were so generous.

Now, as an investor, I'm doing so much more to help people. I, and others like me, are not just creating things or providing services, we're creating jobs, creating businesses, creating an industry, creating an entire economy, and creating a better future for all mankind.

Nobody needs money to survive. You can't eat money, you can't cure diseases with money, though if you burn it you can at least stay warm at night. What people actually need in order to survive is the stuff that money can buy. And the "delusional" desire to acquire money is what motivates people to create that stuff. The only reason you're not starving is because farmers want money. The only reason you have a roof over your head is because builders want money. Pretty much everything that is good in the world exists solely because people want money. That's the reality.

Miners gain because they get paid to do the calculations.
Everybody else gains because these calculations are used to secure the blockchain, without which Bitcoin would be worthless. The blockchain is the ledger of all Bitcoin transactions, and cannot be altered without completely redoing all the calculations used to produce it, which is impossible unless your have more computing power than the rest of the network combined. Due to the massive amount of computing power involved, this is, for all intents and purposes, completely infeasible.

As one of those hoping to become the next Job/Gates/Buffett, I'm insulted. I did not "get lucky". I never base investment decisions on luck. Instead I spent several months in late 2011 studying Bitcoin, and several years prior to that studying and working in IT which gave me the knowledge and experience to actually understand Bitcoin, and I knew, not guessed, but knew that Bitcoin was absolutely revolutionary and had the potential to completely change the world of e-commerce and possibly even banking. Just imagine a world where identity theft, chargeback fraud, capital controls, bank holidays, and exorbitant wire transfer fees are all a thing of the past. And we owe it all too... ME! If it weren't for me (and other early adopters like me) investing their hard-earned capital into this unproven and experimental technology, Bitcoin would not be where it is today, and all the profits I made in the process were the result of many years of hard work and education.

Luck, my arse.

What you are describing are problems with the conventional banking system, which Bitcoin solves. You are simply encountering the usual difficulty of moving your dollars from one place to another (which Bitcoin obviously can't help you with, since Bitcoin has nothing to do with dollars and has no control over your dollars). I guarantee you won't have such difficulty moving your bitcoins around (once you manage to obtain them, of course).

Yes, because "most" isn't the same as "all". The big miners earn more than the little miners, but the little miners still get something, in the same way that big companies like Walmart make billions, but that doesn't stop you making a few extra bucks at a garage sale. Also, remember than mining is a business, in which miners sell their computing power for the purpose of securing the network. It is not a get-rich-quick scheme, or a means of distributing money to random people, or anything else. The average Bitcoin user is not expected to mine, or even know what mining is.

Everyone running a Bitcoin client is a peer, whether they're mining or not.

No. Or if they were in the past, they certainly aren't today. Banks exist to provide loans so that people can pay for things they don't have the cash for. They do this by taking your deposit, lending most of it out to other people, charging those people interest, then passing a portion of that interest on to you and keeping the rest as profit. If you've ever wondered exactly how a savings account earns interest (the money can't just appear out of thin air, after all), now you know.

Obviously, this system only works if the loans are repaid before people try to withdraw their money. If too many people default on their debts, or too many people withdraw their money, hilarity ensues.

Clicking "New Identity" in Tor usually fixes any intermittent connection problems. Also remember that Tor can be very slow at times, sometimes taking several minutes to establish a connection, so be patient.

This is what happened here: blockchain.info/tx/8790bac8cfedfc23a64177fd28ab1ed6ea279c4362550797fbde59ae43c86f82 The real question is why.

%APPDATA% is just a pointer to the application data folder of the currently logged in user on the drive Windows is installed on (which will always be on your C: drive for a standard Windows installation). The folder you're actually looking for is F:\Users\USERNAME\Appdata\Roaming\Bitcoin\ where USERNAME is your user name on your original Windows installation. Copy the wallet.dat file from that folder to %APPDATA%\Bitcoin\ (overwriting the wallet that's already there, assuming you haven't already tried to receive coins with it - make backups of everything if you're unsure) and everything should be good.

Line 100 of the HTML source (the line starting with "data:"). Format is an array of [time,price] pairs. Time is in Unix format (number of milliseconds since midnight 1 January 1970 UTC), price is in USD.

Close Bitcoin-Qt if it's running, then delete the file wallet.dat in the folder %APPDATA%\Bitcoin, and restart Bitcoin-Qt. This file is not deleted during the uninstall process, to avoid losing your money by accident.

Don't know why it would say that. Try quitting Bitcoin then restarting with the -rescan parameter.

You're pool mining, not solo mining (further evidenced by the fact that all your transactions are payments from mining pools). What made you think you were solo mining?