I had a power outage the other night and apparently a spike got through my surge protector. I figured it got the power supply so I borrowed a brand new one to try. The puter fired up and ran for about 5 minutes then shut off again and won't power back on. I had the CASE open and had cleaned everything, checked that the fans were running, etc and all seemed to be going well until it shut off. I was thinking of upgrading the motherboard and processor anyway so I guess this is a good a time as any. My question is....any suggestions for a replacement? I'd like to keep everything else as is for now unless anyone has some better suggestions. It was a good running machine.

This is what I have:

Intel D850GB motherboard
Pentium 4, 1.8 GHz processor
256 MB RDRAM
NVIDIA GeForce4 MX 4000 AGP video card
Maxstor 80GB Ultra ATA/133 hard drive
WDC 60GB WD600AB hard drive
Sony CD-RW CRX1611
Sony DVD-ROM DDU1621
Realtek RTL8139 PCI Fast Ethernet adapter
Windows 2000 ProfessionalWas the PSU you borrowed of good quality & adequate size?
Did you try disconnecting your old PSU from the mains then plugging it back in & BOOTING?
Some PSUs latch into shutdown on mains failure.The old PSU was a 300W Skyhawk. I fiddled around with it some and it would seem to be a hit or miss thing whether or not it would come on. When it did come on, it would shut off right away again.

The new one is an Ultra Xconnect 500W. After I hooked it up, the computer ran for about 5 minutes and everything seemed to be OK then it shut down and won't restart again no matter what I do.Try resetting the CMOS by removing the CMOS battery for ~10 seconds or shortcircuiting the CMOS jumper.

Have you tried booting with minimal hardware attached?Never thought about the battery. I took it out and put it back in but nothing changed. I can unhook all the hardware and nothing happens. The fans don't even turn on now. Seems I just have a big paperweight now.OK, maybe I'm getting somewhere now. When I turned on the power supply, the green light on the motherboard came on but when I hit the on button on the computer itself nothing happened. I took the faceplate off and I'm not sure if the switch might be bad or the connection was just loose but it fired up this time. Since I took the CMOS battery out, the setup screen came on and it said the battery was low. It then booted up and ran good for about 5 minutes then click, it shut down. I'll get a new battery in the morning and try that and also maybe look at the switch again. Wish me luck and thanks for the idea about the battery Raptor.No problem, CR2032 is most likely what you need.OK, I'm back to square one. I replaced the battery, it was a CR2032. Nothing. I tried to HOT wire the switch so it would just turn on with the PSU. Nothing. The light comes on the motherboard but nothing else happens, no fans, no lights, nothing.I know you have replaced it but it still sounds like a psu problem to me.
Is the voltage selector switch set correctly on it?
Are the leads all plugged in very securely?That's what I originally thought in the first place. The selector was the first thing I looked at before plugging it in. I checked all the connections. It's acting the same way as it did with the original psu. The light comes on the motherboard and I hear a "burp" out of my sound card but nothing else happens. I'm completely puzzled.As you were talking about a new cpu & motherboard I think I'd strip it, clean it & rebuild it with minimum hardware connected & then try & boot, even using the old psu.
You don't have much to lose at the moment.Yeah, that's pretty much the CONCLUSION I came to too. It's been a good system for me, maybe I'll be able to resurrect it as a backup. Thanks for all the input, guys.