My computer has been acting up lately. It's a custom-built athlon XP 2400+ with a ATI 9700Pro vid card and a case that has 2 fans and 14 LED's - I am using a 350 watt cool max power supply. It ran fine for months with this configuration.
The past couple of weeks, my computer started shutting itself off for no apparent reason. When this would happen, I could not power it back on unless I reset the power supply by turning off and on the switch on the back. It would boot up fine most of the time and I could resume my work.
This started happening more often. A few times, it shut down while the Windows XP loading screen was up. For some reason, when it would do that, Starting in Safe Mode and doing a system restore would allow me to boot up OK.
I've also had a few problems lately with the video - sometimes the monitor says 'check cable connection' but the cable is connected. After messing around with it, powering it off and on, it would finally work.
Now all of a sudden, when I power up my system, it shuts off after 27 seconds. Again I have to reset the power supply. I even let it sit on the BIOS screen to make sure it wasn't happening at a certain point in the boot process but even then it will shut down after 27 seconds.
Any suggestions would be appreciated.

NOTE: The CPU fan and the power supply fan are both working fine and I do have my computer plugged into a surge protector.

Thank you.

This is weird. Must be a hardware problem if it shuts off after 27 seconds even when it's only in the BIOS.

Sounds like an overheating problem but you say the fans are working OK. Do you have a temperature / voltage readout in the BIOS. Start it up from cold and go into the BIOS and watch those readings. See whether one of them goes out of range so that the system shuts down to avoid being damaged (e.g. overheat or out-of-range voltage, which could be too little as well as too much).

I've just fixed a problem in a PC which kept rebooting as soon as the Windows desktop loaded. Now that I think about it, I did try to slow down the boot process by going into the BIOS etc and, when I did that, it didn't get as far as the Windows desktop and shut down earlier - so maybe that was time-related as well. Anyway, I replaced the CPU and I've run full testing on it (restarts, power offs, lots of software installs, Internet, etc) for about 8 hours and it's been perfect all the time. Not saying that's what your problem is .... but it's a possibility.

Would also be worth temporarily unplugging a few things, such as your LEDs and your CDROM drive, to see if that helps it chill out a bit.

It was the power supply. I think I was overloading it. It finally petered out and the fan wasn't spinning anymore. I replaced the power supply and unplugged a few of my 'extras' until I can afford a 400w or better. Thanks for your help.

If you want to future-proof your system a bit more, I've even seen 550-watt PSUs in some online shops. That should cope with your LEDs - you could probably run a small floodlight off of it!

Glad to hear you got to the bottom of it. Thanks for the update