R40 Graphical Display Problem

[aPanzerIV]

Hey, I've got an R40 here, and it has had a problem since i got it a couple months ago. I assume its a heat or power problem, since it doesn't happen when its on battery or low power mode. At random points in usage, on ac power only, the display will get artifacts and fuzz stuff on it. There really is no specific point in when it does it, it will just randomly start. I can play an entire game of CSS without it starting. It does not stop automatically though. You have to press on the corner area of where the keyboard/keypad meets the hard drive caddy. Sometimes you have to press hard to get it to stop. We took it apart and tightened up some loose screws/other things. It does it less often now. If you leave it unattended while it is doing this stuff, the screen will at some point go white all the sudden. Another R40 I got (different config though) did this when it got hot, but would stop when you press it, or after a few seconds. I've seen some on youtube, but none of them are this one in particular.

R40 with the problem:
Type 2897-GWU
1.5Ghz Pent. M Banias
1280mb DDR (upgraded from 512mb)
32mb ATI-7500
60GB IDE
Windows XP Pro SP2
1400x1050 screen

Other R40:
*sold it, so can't find the part no.*
2.4Ghz Pent. 4 2.4Ghz
1280mb DDR (upgraded from 512mb)
32mb ATI-7500
60GB IDE
Windows XP Pro SP3
1400x1050 screen

Thanks