Hi, i have a question for all the hardware experts here...

I am running Windows XP Pro with:
XFX Nvidia Gefore 8600 GT XXX
2 Gb of DDR2 Ram
AMD Athlon 64 4400+ Duel Core processor (2.30 Ghz)
Not exactly sure what Motherboard i have...

about a week and a half ago my computer started to play games (ex. Left 4 Dead, TeamFortress 2...) a little laggy from time to time. Then last Saturday, i left my house for about 4 or 5 hours, came into my room and noticed it strongly smelled like plastic burning (the kind of smell you get when you use a solder iron). From then on i couldn't play more than minute, and even then it was if i restarted my computer, on any game without it going very slowly. It didn't matter if i was running Team Fortress 2, or that 5mb game that mercuryus put up...

Anyway, i was wondering if my graphics card over-heated and i would need to buy a new one, or if it is something else entirely.

Edit: forgot to mention that i can still have a high resolution - 1680 by 1050

Any help would be greatly appreciated