What is the best way to check my temperatures?

I recently had my videocard overheat and get a ton of artifacting. First the computer got a ton of artifacts in windows and went to the blue screen of death telling me that nv4_disp (the vid card) had gotten stuck in an infinite loop. Then when I tried rebooting the splash screen, bios and windows loading screen all had terrible artifacts and the monitor shut off as soon as windows booted pat the load screen (still heard the startup chyme.) I've had the laptop for three years and this is the first time I've had a problem like this. I've preloaded borderlands and I wanna play it when it comes out, but I'm afraid to turn on the computer.

I just took the bottom panel and blew out the vents and fans, there was tone of dust and some big clumps (about the size of a bb). I don't know if this will help but I want to closely monitor the temperature and watch for overheating.

Is there a program that monitors the temperature, how do I safely test temperature performance during game performance without frying machine

 

You can try Everest or HWMonitor for temps.
Also read this thread.

 

Tray Speedfan or everst or CPUID Hardware Monitor. CPUID Hardware Monitor is best in my opinion. If your overheating , you can undervolt your processor. Also get a notebook cooling pad and this will help in lowering temps by a lot.