Compaq keep rebooting

[i2omani]

I have this customer computer its Compaq Presario that keep rebooting it self and comes back.
I checked the temp and its constantly at 39F.
It has no specific time on when it will reboot? does it 3 times a day?

what could be the problem?

 

[Jm Boyd]

Could be a heat issue with the Power Supply. Check the Power Supply Fan to make sure it is running and the blades are clean. Then clean any dust and debris out of the Power Supply with a can of compressed air.

 

[Artimus]

Disable the automatic restart when a BSOD occurs. The box could be BSODing and you wouldn't see it.

http://helpdesk.wisc.edu/page.php?id=7049

 

[starfireone]

Might be bad memory. Seen memory do the exact thing to me on a PC. Try reseating your memory and try setting the bios settings to fail safe defaults.