Is it always the same game?

Also, memory leaks are caused by programs not freeing memory that it has allocated, the only time it'd cause anything like this is if it was allocating huge chunks of memory and not freeing it.

Hmm, it happens on any game, and for some reason, everytime I launch a game these days, they just minimize. Which brings up another part of the problem; When I minimize some games, my mouse cursor vanishes. I can still use it, but it doesn't appear...

Could you install speedfan and run a few intensive apps and see what the temps are?

I don't really know what to do with this program.. My PC keeps finding Trojan Horses in system32 aswell.... But even if they're removed, the problem remains.

you should download AVG or another anti-virus, run it, runs anti-spyware. If your computer wasnt so powerful, i would say that the game or whateaver was hogging the CPU time, which would cause the things to act that way. i had that problem with my old Pentium III computer. Try doing what lebowski said, then let us know what happens.

With speed fan it should give you some temperatures when you open, tell us the temps.

Do a virus scan in safe mode AND do the prework.

I'd pretty much forget about the whole 'Memory Leak' thing as it would be more people having the problem than jst you and there would be nothing you could do if there was one, short of putting ina bug report to the developers.