problems comp restarting

[DarKCoW]

hey i just bought a new comp, custom made
400 watts,1 gig of ram, pentium 4 3 ghz, 4 case fans, nvidia vidio card.

im running on windows 2000 xp pro and seems to run fine when just vewing websites and such. but when i play
Counter-stike, a mod of half life which needs steam (a bad program), i can play for about an hour or so but then it suddenly reboots without any warning. after that i checked the cpu temp and it was about 50-51C, dont know if that might be the problem. I restart the program and then it reboots in 10 mins??? thats confusing me. dont know if its the program or what. it seems to run other stuff just fine, such as any game will be able to play on this comp instead of Counter-Stike.

My freind who put it together also has a custom comp and didn't have any of these problems

PS. i have done this about 3 times, same results, and this system error report has been coming up. can u tell me what these files are?
C:\WINDOWS\Minidump\Mini031304-01.dmp
C:\DOCUME~1\Eric\LOCALS~1\Temp\WER3.tmp.dir00\sysd ata.xml

[ECA]

1.
is this XP or win 2000
2.
have you optimized your system, Killed all the stuff in the background.
3.
YES, steam sucks.
4.
If its win 200(I have that also) when it restarts for no reason, it chacks what happened and what was running to see if they are corrupt.

The minidump is from HL. READ it with a txt reader. send it in, IF you think it will do any good. should post this on the Steam site.
As for the document/locals/.....sysdata.xml Im not sure what that is. but seeing the 'xml' on the end, i would try to open it with a TXT reader or IE.
Im wondering if theres a BOT on your system. You also dont tell us HOw you connect to the web, 56k, highspeed, or what.

[ECA]

PS,
Yes I get slammed most times I play HL.
It dont matter what, DOD, HL, TF, CS, after a time, I get Locked up.
Generally between maps, and esp during a new map.