[someconcerns]

This is a compound question.

Older HP P4 2.6 GHz desktop was put away for a year. Just tried to boot it up to update it and computer turns right on, but no display comes up on the monitor and monitor goes to sleep. Tried 2 known working monitors, starting with the one which was used on the PC and both seem to be getting no signal. VGA plug was tightly attached in both cases, as were keyboard and mouse Had to pull the plug to turn PC off.

Next, when I plug the PC back in, the hard drive just starts churning away as if it is booting up.

So questions are: did the video card somehow go bad on it's own? Why does the HD just start churning when I plug in the PC (without pressing on button)? And what do I do?

Thanks for the advice.

[Scleros]

what do I do?

Given that the computer has set idle for some time, try this:

1. Open computer up and verify nothing crawled into it and made a nest. Clean if necessary.
2. Remove and reinstall video adapter card and memory modules. Warning: Power cord needs to be completely disconnected and any power status LEDs on motherboard drained and off when this is done.

Since the drive has activity, suspect that it is a video issue.

did the video card somehow go bad on it's own?

Maybe, or it could just be poor electrical connectivity which removal and reinstallation will normally resolve.

why does the HD just start churning when I plug in the PC (without pressing on button)?

If there is a BIOS power fail option and it is set to "Last state", it would boot immediately since the cord was pulled to shut it off previously. Pulling the cord should be the method of last resort. Modern machines will power off when the power button is held for several seconds, although the behavior is configurable in the BIOS on some machines, so this technique is not guaranteed.

[someconcerns]

I'll see if I can get it done this weekend. May have to wait until Monday. Thanks for the clues!