Just to follow up what Ardell Faul was saying, I had a dv9000 a few years
back that had a similar issue. I had it set up to dual boot WinXP and
Ubuntu 8.04 I believe. I started getting lines on the display as you
describe, but only when I booted into Windows. Windows finally stopped
working completely, but I could work just fine with Ubuntu. Because Ubuntu
was working and Windows was not, I had also assumed it was a software
issue. After about 6 months, Ubuntu showed signs of failing as well, and
finally died. When I researched more, I found as Ardell noted that there
is a problem with the video chip on these motherboards. The heat sinks
were not designed to properly cool the graphics chip and after a relatively
short period of time, the solder points loosen and need to be reflowed.

A new motherboard would have cost about $300, so I did some research and
found a time/temperature chart for solder reflow. I bought an infrared
thermometer, made a heat shield out of an aluminum can and some tin foil to
protect the rest of the motherboard, and then used a heat gun and a timer
to reflow the solder on the chip. I also bought some thin copper sheet to
improve the contact with the heat sink and cut it a little larger than
necessary to help disperse the heat better. I figured, hey, if its already
broken, I can spend $30 to try and fix it, or $300 for a new motherboard.

After I finished the process, both the Windows installation and the Ubuntu
installation worked like nothing had ever happened. I got another 3 years
out of this computer before the same thing happened again. I tried to
reflow again, but I think I toasted the chip. Oh well. I was ready to
move on by then.