my Acer Power F2 shuts down

[boltes5]

help me please..my Acer Power F2 desktop pc is shutting down after several minutes. I checked the OS (no virus), power cord, the avr and power supply everything is ok, except that it shuts down at the middle of my work. here's the specs:
                                        Processor - Intel Pentium 4
                                        RAM - 256 mb ddr 400
                                        HDD - 20g
                                        OS - Windows XP Prof Service pack 2
                                        Video - built-in Intel Graphics Accelarator

[Crafty]

Could be an overheating issue - Remove the side of the case and if you have a desktop fan use this to blow into the open side. This is just a test to see if its an overheating problem.

What temps is your cpu reaching.

Another thing it could be is your ram. Reseat the ram by taken it out and making sure its reseated properly.

[Broni]

You need more RAM, as well.

[boltes5]

I've already open the side cover and put an electric fan facing the cpu yet it shuts down. I even disabled in the cmos setup the shutting down temp. as i've observe when temp reaches from 38-40 degees C it shuts down. but dont tried to reseat my ram.thank you for giving that option.

[Carbon Dudeoxide]

Does this still happen in Safe Mode?

I checked the OS (no virus)

How did you check it? (what antivirus software do you have?

Any recent downloads/installations before this happened?

[friny]

Check the PSU fan, It could be broken!, When the PSU is overheating the PC turn off to prevent a hazzard risk! Try it! Check also in the BIOS the temperature and check if you have active the overclocking option!

Regards