Don't forget some "oblivious" items:
Flakey AC power connection to the monitor... wiggle everything and see if you can make a significant change in behavior, either far better or far worse.
1) bad power cord (swap it for another one)
2) bad outlet 'hole' in power strip/surge protector (try another one)
3) bad outlet in wall (wiggle plug, but best check is try a two-prong plug from something that you know plugs in "firmly" elsewhere. If it slides in with very little force compared to what you know is good, replace it. I've had experience with this, especially with the (used to be) 59¢ cheapo outlets sold by Home Despot.)
The reason I bring this up:
I'm guessing that the OP is probably still running a CRT monitor due to the age of his computer (512 megs RAM and running PhotoShop???). I'm guessing somewhere between '99 and '03 from "P4" and "512". The generation of CRT monitors out at that time could also have "bad caps" (see http://www.badcaps.net/pages.php?vid=4)
What's interesting is that bad caps in a monitor may only show up on short power glitches caused by the above problems (and the symptoms are what the OP has). Even though the pooter may live past the same glitch (even with bad caps in the power supply), is because the power loads are totally different.
So it's possibly a "double whammy". I've seen numerous problems with more than one true fault. It's like archaeology, you find one just to uncover another buried under it.
In case you hadn't guessed, I've been both an electrician and an electronic tech (sometimes both at the same time) for years. Two phrases best describe my background; "DC to Daylight", and "Widebanders Do It Till Their Gigahertz".
Edited by Memphis T-shirt, 18 April 2010 - 07:22 PM.