OpenGL Error!

Ive isntalled several games in my computers usually online games such as gunbound, mu, ragnarok. i have also several offline games… the problem is when i played several games for several hours there are situation that open gl and directx error occurs when starting a game. i need to restart the pc to make it stable and continue to play my games… btw im using win2000 professional, on nvidia chipset mx 400 64 bit on sempron processor

Could be a thermal problem or simply a background process that is leaking resources…

Nothing OpenGL related anyway.