Problems running games

[Zephyr6]

The game I'm really trying to run right now is Battlefield 1942. It works fine on my computer, even loads the maps decently fast and I don't lag at all (unlike my friend's computer...). My problem is that after I play the game for around 5-10 minutes, it closes, everytime. Sometimes my computer just restarts on it's own right in the middle of playing. I can't figure out whats causing it. This isn't the only game this ever happens with either. Every so often games like Diablo 2 just close, but it happens VERY infrequently with D2 and it never restarts.
My system is:
Amd athlon 901mhz
384 ram
GEFORCE 4 video card

and ideas on what I could do?

[amd_man2005]

Most likely your comp. is overheating.

[Neil2094]

I would have to agree get a desktop fan leave the side off the comp to check if its overheating. If it works wack a proper case fan in there.

[Whoever]

If heat isn't the problem it could be that either you have an underpowered power supply or an unstable RAM module. Try using only one of your ram stick at a time, alone, or different RAM altogether to see if thats the cuase. Also make sure all your drivers are up to date and you have no hardware conficts.

Battlefield 1942 runs good on that system otherwise? Thats surprising becuase that is a very system demanding game. You must have to turn the settings down abit from defualt just to stop the lag.

[syx]

May be ram problems, when ram is defective you can have random reboots, happened to me with pc-133 and new DDR333.

[PersianImmortal]

Sometimes my computer just restarts on it's own right in the middle of playing.

99% of the time sudden reboots are caused by RAM. Either your RAM is faulty, or your memory speed (in Mhz) is too fast for the rating of the RAM, or the timings on the RAM are too aggressive (e.g. 2-2-2-5).

[smokin_pc]

i have had the same problem of restarts in games. I had a bad cooling sysytem, and my ram was those refurbised ones. so, i got new ram, and set the cas setting to 2.5 and i had a stable system.