I'm having a problem with an old computer that is at least 8 years old.
Last week the power supply on it died, so I replaced it with a much newer one I had.
On initial boot everything looked great, I checked my email and then shut it down. Just to make sure everything was really ok, I started up again. There was no display. The computer started up and everything but the display worked. All the fans worked, the hard drive worked, the CD drive worked... I could hear all the windows sounds, then MSN messenger sounds, then Skype going online.... but couldn't see anything.
I unplugged the monitor from the AGP video card and plugged it into the onboard VGA slot but still no display. (I'm not sure if the onboard works or not... it may not.)
Then I shut it down and power cycled it. Unplugged the power cord, pressed the power button, plugged the power cord back in. And started it up. Everything works. I have display, everything looks and acts normal... until I shut it down again.
When I restart (as opposed to shut down), the display will work restart after restart. But if I shut it down and then start it back up, I get no display.
Other info that may or may not be relevant:
1)The old PSU had both molex and sata cables and everything in the computer only used molex. The new PSU only has sata cables, so I bought sata to molex adapters to make it work.
2) The mobo takes a 4-pin power source while the PSU only comes with an 8-pin. The 8-pin is not designed to be broken apart and there's no safe way I can cut it. I couldn't find an 8-pin to 4-pin adapter (since it seems that most 8-pins are 4+4pins, but not mine.) So I ended up using a molex to 4-pin adapter. I underestimated how many sata to molex adapters I would need, so I had to use molex splitters to get everything hooked up. The 4pin adapter is on a molex splitter with the hard drive.
3) Since I was swapping the PSU anyway, I figured I might as well put it in a better looking case. So I unplugged everything from the motherboard and tried to move it to the new case but realized that the new case had different screw holes. Instead of messing with it, I just put it back in the original case and hooked everything back up. I'm 98% sure I plugged everything back in correctly. Just to be sure, after I was having these issues, I reseated the ram, video card, and rechecked the hard drive and disk drive cords.
Motherboard: Gigabyte GA-K8VM800M
Video Card: Radeon X1300 PRO AGP 256M
I thought that maybe on subsequent start ups the system was choosing onboard video over AGP, but I can't figure out how to make it stop. In hidden BIOS options, the choices for Init Display First are [Onboard/AGP] or [PCI]... So I have to leave it set to Onboard/AGP.
I suppose there are worse things than having to unplug/power button/plug in/power button before each start up, but I'm hoping someone here can help.