RO slowing down Win XP

[Arkenion]

Hello,

When I play RO for about two or more hours, my computer gets really slow. It is definitely not because the computer itself is too slow, I'm playing in safemode and have really high FPS, I could even play with everything on highest and shader 4.0 and I'd still have about 60 FPS, but I don't do that because of another problem. Anyway: The strange thing is that even when I disconnect from RO, the problem remains. It's like I was running way too many programs and the computer would be overloaded.

I'm a real PC noob. Is it the Ram that is overused, or the CPU?
Whether it is this or that, it must be a bug or something because it's surely not the computer being too weak. Also, I didn't have this problem until some weeks ago. Can't really tell when it started to occur though.


Some general computer informations:

Win XP SP3
Intel Core 2 Duo 3.00 GHz
2 GB Ram
NVidia 8800 GT (newest drivers)
RO in safe-mode