You don't know much about BTC and already programmed a new online wallet? Respect.

just wanter to reply: hi !

Nobody reads forum rules before registration. You are normal 

The answer is simple. Hacked Paypal accounts. There is whole world of hackers waiting to buy btc with stolen paypal passwords. Finally the original owner of Paypal account knows about being hacked and asking for a chargeback while the hacker gets bitcoins which is not reversible transaction. This is why you loose.

The most important thing is that investing in BTC mining hardware is very risky now. Even one week of a delay can put you from getting a profit to getting a small loss. There are some manufacturers that are late like 13 months (BFL), there are other with being late 2 month (Avalon). Their customers will never see roi. Watch out also for in stock devices, blade erupters and usb erupters are overpriced and most probably will never see a roi as well. It is very risky now to invest in mining software. Not recommended for newbies.