I will only say this then leave further posts to others, because I may be incorrect.
From that image you posted, this does not look like a software problem, but a hardware one. Perhaps either a video card or possibly RAM.
I had similar, (but not the same), bars across my LCD monitor a while back, and had to replace the video card.
If I recall, I tried to install Windows XP service pack 3 but I had trouble doing so. Then I had to resort to doing something to the registry, which allowed me to install the service pack and also fixed the error of shutting down the computer (originally, the computer would freeze after shutting down...computer stuck on "Windows is shutting down" or something like that).But now, the computer would randomly freeze after turning on the computer. I have to press the power button on my computer several times a day in order to use the computer. I wanted to take the computer to a person to fix it, but I don't have the time. I tried Advanced System Care Professional, but that didn't work. I tried other programs that cleaned the registry, but to no effect.
The link to what it looks like when it freezes...
Microsoft Windows XP Home Edition
Service Pack 3
Pentium (R) 4 CPU 3.00 GHz
3.00 GHz, 3.11 GB of RAM
HP Pavilion a730n