A couple of weeks ago, my Powerbook G4 started behaving a little oddly
(after a year and a half of ownership, but a recent logic board
replacement). A horizontal red bar showed up under the top menu bar,
and very thin vertical red lines showed up on the display, apparently
tied to moving windows. So I reinstalled the OS, which seemed to take
well enough, until I had the same thing come up again tonight. The
display itself does not seem to be damaged, as those bars only show up
when the finder starts; the background is normal when it starts up
with my login screen and before the menu bar appears.

I played around a little with the display options, and changing the
display size to something else and back again got rid of that for now,
but I'm wondering if anyone has had a similar problem, and if it's
anything I need to worry about, or something I can find a permanent
fix for? Thanks!