Hello,Our power to our house shut off one day for only a few seconds,when it came back on the computer did not,I checked the power supply and it was not working,bought a new 550 watt power supply,it worked for a few days then it quit so I took it back and he refunded me my money,I went to staples and bought a 350 watt power supply but the PC kept shutting off,this happen a few min. after the processor fan came on,when the PC was new,ever sense the power shut off that day,when I start the PC the fan runs so slow I can't hear it,but as soon as I get on line the fan starts running,fast then slow at first then gets quite,then right before the PC shuts off the fan comes on fast,the first new power supply I installed,when it quit the power light quit coming on but the processor fan did run,the mouse did light up but the monitor did not come on,just said no signal,could my processor be damaged
could have two issues. one when the ps dies it could have zapped the mb. there may be a damaged part or cap on the mb casuing the ps and pc to shut down. if it not a power issue it could be that the cpu heat sink the thermal paste gone bad from age or the cpu heat sink not seated or the fan not moving. I would pull the side case off and clean any dust out. I would then boot from a hirem boot cd run a anti virus scan and see if runing a dos disk the pc shuts off. hirem boot cd has mini xp you can see if your system shuts down going into xp. if it does then in xp download hardware monitor and check the cpu/gpu temps and look at the ps voltage going into the mb. cpu geting to hot the mb going to shut down to save the cpu.