I'm running an old P4 from 2004 with a GeForce FX5200 fanless graphics card, hooked up to an LG Flatron F700P CRT monitor. I only use it infrequently, partly because it has trouble booting; there are two or three points during the early boot sequence at which it can hang unless it's properly warmed up (by cold-booting it and letting it hang for a while). This may be related to what looks like a blown cap on the MB. But that's not what I'm posting about.
What I'm worried about is that when it is running, I get intermittent flashes of glitched horizontal lines in the picture. They seem to happen in clumps (forming horizontal bars in the picture, which are mostly but not entirely non-solid) and show some consistency in location between flashes during an event (which generally takes a small fraction of a second, but clusters of events can span a couple of seconds before the display quiets down again). The glitching shows unusual brightness in some areas, which would seem to imply an analog problem. I've never seen it happen when the screen saver has the display blacked out. Sometimes it seems like it's triggered by using an input device (e.g. pressing a key on the keyboard), or taking the cover off the case, but usually those actions don't cause it, and sometimes it happens for no evident reason at all. And it seems to be more frequent since the last time I used the computer...
EDIT: The problem seems to go away as the computer (or the monitor?) warms up. I haven't seen it in a while now.
Any idea what's going on here?
What I'm worried about is that when it is running, I get intermittent flashes of glitched horizontal lines in the picture. They seem to happen in clumps (forming horizontal bars in the picture, which are mostly but not entirely non-solid) and show some consistency in location between flashes during an event (which generally takes a small fraction of a second, but clusters of events can span a couple of seconds before the display quiets down again). The glitching shows unusual brightness in some areas, which would seem to imply an analog problem. I've never seen it happen when the screen saver has the display blacked out. Sometimes it seems like it's triggered by using an input device (e.g. pressing a key on the keyboard), or taking the cover off the case, but usually those actions don't cause it, and sometimes it happens for no evident reason at all. And it seems to be more frequent since the last time I used the computer...
EDIT: The problem seems to go away as the computer (or the monitor?) warms up. I haven't seen it in a while now.
Any idea what's going on here?