Freezing win 7... Any solution?

Hey, how are you. First of all, I'll start by saying that I have not money to buy the original windows 7 (and I'm not happy with that at all). So, I have to use a loader to get my copy of win running. The thing is that after I install, everything goes well, until a point when my win 7 ultimate start to freeze.. It freez at around 10/15 min of starting. The funny thing is that if I start a game in the first 5/10 min of starting up my pc, it won't freez at all! I close the game... And it won't freeze... Or sometimes it will, but when in game, it won't freeze. That really strange, right?

I was wondering if it could be the loader ( I've tried a couple and the same happens)... Well, you are the expert.

Please, could you help me?


Thanks in advance.

Quad core 2Ghz
5Ghz ram
760gb hard drive
Win 7 ultimate ( using a loader)
Ati radeon (big one!)
Power source (up to the task)