I have Ubuntu 8.04 running on an IBM Thinkpad T40, my problem has just recently started occurring, in which the screen starts having horizontal lines appearing. The lines are almost like smears of the screen, most notably on vertical lines and on text. The lines are initially tolerable; however they end up making the machine unusable once the small smear becomes almost an entire line across the screen. It ends up looking more like horizontal fuzz (like video snow...just not dots). I want to say this is a heat problem since the laptop this occurs on gets noticeably hotter than another T41 I have. However, the fuzz can be eliminated by firmly pressing on different parts of the laptop (sides of keyboard, center of underneath, etc. It is like something is loose. maybe?
I have changed the resolution without any resolution. Ubuntu does not detect any other refresh rates I could try and the last time I got my hands into Xs config I ended up having only terminal for about a week, so Im a bit gun shy (I have other things to study currently than my display config).. Also considering the symptom I highly doubt it has anything to do with the config, it was working fine until about a week (maybe two) ago.
Memory load does not seem to affect the issue either, though it does seem to escalate faster with more use in general.
Anyone got ideas? Things to check?