BleepingComputer.com: Completely Stumped

Okay, I usually can fix minor issues with desktops. This one has me so stumped. I have a secondary backup computer that is ANCIENT. Running XP, it is a Compaq Presario SR1030NX, with 512MB Ram, 160GB Hardrive with a 3000AMD Athelon processor. I was updating my anti virus, but after 10 minutes the screen goes blank. The hard drive is not running, the monitor is fine. I re boot and I get the black screen screen that wants to either start safe mode or normal windows. Start normal. Try again, different program, still an anti virus though. Try to scan and the computer blacks out and this time after it blacks out the hard drive stops as though I had fully shut down the computer. Monitor has not gone to sleep, and the idiots lights are on the tower, but the activity light, the fan & the hard drive are not functioning. Re Boot and the same black screen, not even scan disk or blue screen. Please help, I don't want another paper weight.

As neither your fan (I assume you mean the CPU cooling fan) or the hard drive are running this sounds like a failing power supply. Or, it is shutting down because the CPU fan has failed and it is overheating.

At the end of your post you refer to "the same black screen" do you mean the boot options screen?

Take the side of the case off and see if the fan is running when you first start the PC?

Are you still seeing the POST screen when you switch it on?

I do hear the fan as it turns on. I have not noticed anything hot. Yes I did mean the boot screen. I took off the case and I can see the fan working. Thank you for the fast input, I will get a new supply, as they are rather inexpensive and try that. If it continues, I will let you know. Thanks again.