Overheated computer games

I have been the problem that my CPU overheat when I play a game. When I look in between times, it reaches peak temperatures of around 120 ° C. How can that be? What can I do?

System:
Windows XP SP3
Dual-core AMD Athlon 64 X2 4400 +
2048 MB DDR
Sapphire RADEON X1600 PRO (256MB)
2x SAMSUNG SP2004C (200 GB, 7200 RPM, SATA-II)

At 120 ° C your CPU would be long dead!
Or is a selection error, games times the current BIOS.

See few threads here about overheating : http://forums.techarena.in/tags/index.php/cpu/5/