Computer Resetting Without Warning

Hello,
My computer is resetting without warning, sometimes during a program (video
editing, encoding - processor intensive stuff) and sometimes immediately
after turning it on for the first time fn the day.
I'm at a loss as to decide why.
Anyone any thoughts?
I'm leaning towards the PSU not being powerful enough but don't want to go
to this expense without being sure.
Is it the BIOS shutting down the machine after a certain processor temp.
perhaps?
Many thanks,
Will Hay
--
AMD XP2000+
512MB PC133
30gb IBM Primary HDD
80gb & 120gb Maxtor on a PCI controller card
Antec 340w PSU
Panasonic DVD-R/RAM on secondary master
Lite-on CDRW on primary slave
Lite-on DVD-Rom on secondary slave
ATI 64MB ViVo Radeon
Soundblaster 1024 Live!
(1 x additional case fan BTW)

Could be XP hit a wall and rebooted.

You could turn the rebooting off to see if that's it.
Control Panel/System/Advanced/Startup and Recovery/
Uncheck "Automatically Restart"
--
Ed Light

Smiley :-/
MS Smiley :-\