Pc hangs when playing games

My pc always hangs when im playing wc3 or any other game.

When i'm playing for a while the game just completely freeze and cant do anything except for reboot.

I already change my monitor refresh rate n war3 refresh rate to 60 hertz. Still not sure what is the problem.


Operating System:Windows Xp pro
System Manufacturer: P4M80P
System Model:AWRDACPI
Processor:Intel Pentium 4 CPU 2.66GHz
Memory:510 MB
Direct X Version: 9.0c

Name:Radeo 9200 series
Manufacturer:ATI technologies
Chip Type:Radeon 9250/9200 Series AGP
Version:6.14.0010.6614(english)
Date:5/4/2006

I'm not very good with computer so please help me.
I just wanna play my wc3 back.