Computer randomly restarts itself

[computerhope]

Im trying to fix a computer that belongs to my brother, He complains that his computer has restarted at many occasions, one has been right before logging in to winXp, another while trying to start the game "americas army", and at many times just opening a cd to play music from it.
Here are the computer specs

Microsoft WIndows XP
Home Edition
version 2002
Service Pack 1
AMD Athlon(tm)XP 2000+
1.67 GHz
512 MB of RAM
GeForce 2 graphics card

FYI
there is also a wireless adapter connected to it , in part with 2 other computers connected with wirless adapters for cable internet.
Thank you, Ruderalis

[MetalMilitia]

What may be happening is the PC is 'BSODing' (blue screen of death) but automatically restarting becasue its set to restart in  'startup and recovery'. This is found in Right click my computer > properties > Advanced tab > startup and recovery. uncheck the box that says 'auto restart' (or somthing to that effect). Now that is disabled you may be able to see a blue screen of death at the next crash, on this you need to take a note of what files are associated with the crash (e.g. nv4disp.sys)  then post it here and someone should be able to tell you whats wrong.

note.. im not on an XP machine at the moment so the way to startup and recovery may not be exact. just look around in the my computer properties and you should find it.