Disagree. The bitcoins are sent. Soon we will see them in our accounts.

If I don't make a mistake, the difficulty just decreases very slightly and the network has not been finding blocks at the same rate as before so the rewards should be lower in average.

If they were a viable menace to cryptography in general, every secure communication in the world could potentially be compromised, including web sites, digitally-signed emails, and so on. If that stage was to ever be reached, I'd be a lot more worried about credit cards and bank accounts than Bitcoin wallets.

The profitable way to use these kinds of technology would be to simply mine altcoins on a multipool, trying to do anything else would likely cost more then it would generate in revenue.

Based upon the number and type of questions you're asking, my guess is you haven't done a lot of personal research about Bitcoin.

First, despite what anyone is telling you on this forum, *nobody* here knows what the true state of quantum computing is like.   It's been asserted in this thread that quantum computing is nowhere near the point where we can crack SHA-256 with it.  This is almost assuredly true given that there is no known instance of quantum computers wreaking utter havoc on everything.  I'm pretty certain that if such an advanced computer existed, someone somewhere would have blown something up with it a long time ago.  But, when you go off talking about supercomputers, this is different than a quantum computer.  Currently, even an entire cluster of supercomputers wouldn't push the difficulty very high -- the network is currently *far* more powerful.

Second, if that's the best plan you think a bank could come up with, let me tell you something -- it sucks and is somewhat laughable.   As I just alluded to, supercomputers would definitely not be the way to go here.    Forcing some type of scenario where the profitability of mining drops to zero or becomes negative is somewhat pointless if all you're trying to do is stop people from mining.  Mining will always move towards an equilibrium between cost and benefits -- if difficulty increases to a point that threatens profitability, miners will drop out, and when the difficulty goes back down after they drop out, you'll see miners jumping back on board.

Third, even if you did have a quantum computer that was powerful enough to crack SHA-256, then believe me when I say there are a *lot* more profitable targets than Bitcoin.  

Fourth, what would it matter if they "drop the rent of supercomputing power?"   Aside from the fact that I mentioned earlier that supercomputers are little wimps compared to the Bitcoin network, how would making hashing power more affordable threaten the network?  

Currently, as I see it, the easiest way for a large entity to kill Bitcoin would simply be to buy enough ASICs to gain a majority share of the network hashrate so they can control it at will (or just buy and sell a large, random number of BTC every day to make it intolerably volatile for an indefinite period, but let's forget about that one for now).  A few billion dollars ought to be enough.  But then the question comes -- "WHY?"

Why spend a few billion (which, even for a bank, is a sizable amount of money) to kill a market that's only worth a few billion in the first place?  All this likely means is that one bank is now out a few billion dollars and are thus economically weaker compared to their competitors (i.e. other banks) who never spent even a penny.  Is a bank really going to sacrifice market share to its competitors based upon some *potential* treat?  Now, if the market cap of Bitcoin was tens or hundreds of billion dollars, this would imply that the network hashrate is many times greater, and now it becomes difficult for even a bank to scrounge up enough money to purchase the hardware required to gain a majority share of the network.

TL;DR:  Bitcoin has natural incentives built into it's core model that dissuade people from attacking it.

Bitcoin price skyrockets due to its limited nature. Miners are rich from past reserves. Bank gives up. Miners earn money from transactions.

Eth.

As was pointed out above quantum computing would not be a very efficient way to hash.

websites such as overstock. take days to deliver goods. so its easy for them to wait for confirmations. but as for the "starbuck's" scenario of waiting 10minutes + for payment before they even pour the coffee into a cup. that is simple to get around

PRE-PAY (research: officially called offchain transactions)

imagine starbucks had their own online wallet service you register and deposit lets say a weeks worth bitcoins for coffee and cookies. and thats confirmed on the blockchain. and starbucks 'credits your account with that X btc

now when you physically walk into starbucks you pay using the starbucks wallet and pay through the wallet. the starbucks wallet is nothing more then a sql database balance to show how much people have pre-paid.

that way starbucks know they are getting paid, because technically they have already been paid. the customer is just agreeing to drop his balance by X amount on the stabuck sql database (offchain).

If you want to be sure, add it to exceptions list if avast has this option.

It probably doesn't even document it, if it wasn't windows itself then only option is antivirus action, isn't it?

Hmm...then antivirus had to do it probably, what one do you use? I know it didn't warn you but you may have overlooked it or it could do it without asking.

Yes, windows sometimes asks if it can delete unused shortcuts at least it happend few times to me it doesn't uninstall the whole program, just the shortcut. 

Are you sure windows didn't remove it as unused program?

Is it possible that your anti-virus is thinking Armory is a virus and removing it? Try seeing if Avast keeps a history of virus removals.

in normal bank note terms a double spend is when you hand someone a $10 note, they mistakenly hand it back as change and you can spend it again..

in bitcoin terms it SHOULD BE:
where a bitcoin is sent to 2 destinations (transactions) and both get confirmed..

this true double spend NEVER has happened and cant under current bitcoin conditions.

but anyone can send out the same transaction twice. but only one will get confirmed, and the other transaction wont get a confirmed bitcoin to use.
now the problem is that some places accept unconfirmed transactions and release products, goods or services even before its confirmed, which from a human observation of handing out funds and receiving goods is considered a successful double spending. but observing the blockchain is not a successful double spend.

basically do not hand out goods, services or products before the received coin is confirmed, and you dont have to worry about double spends

https://blockchain.info/double-spends

in short:
you wont find a single output being used twice where both destinations get confirmed, its purely about the merchants noobness to hand out funds/goods before confirmed