Last night I shut down my PC, as windy rainy weather was predicted (I didn't want to get tongue lashed by Windows for an improper shut down, if the power goes out). I usually have the PC on 24/7.
And the last month or two I see some interference in the VGA video. Okay, must have a ground loop issue, but I kept punting on resolving it. Well, when I tried to power up today, the PC would turn on for a half second and go dead. Unplugged various loads (hard drives and such) but no joy. I did have another power supply I salvaged out of another Dell PC, hooked it up in place of the machine's power supply, and now the computer works!
Did a proper power supply swap out, and then I opened up the old power supply, and yes, an electrolytic cap bulged, gone bad. And a little later I noticed that the video VGA interference is no longer present.
I'll get to changing out that bad cap (probably should change out the other ones like it), but for now I'll run on the swapped power supply.