Question : Problem: Dimension 5150C Pentium D powering off

I have  Dell Dimension 5150C  Desktop Pentium D running on Windows XP that is powering off. I am working on something and I get the "starting power safe mode" message and it just turns off and I have to click on the power button to turn it on again. I already went to the Power options in control pannel and selected to never shut down or hibernate. Any idea?
Thanks in advance!

Answer : Problem: Dimension 5150C Pentium D powering off

1) Do you have a UPS plugged into this machine ?

2) have you checked that nothing is overheating ?

3) Also check the BIOS settings regarding power options.
I hope this helps !