Vertical lines on start up

[malago]

Please help

When I start up my screen is filled with a load of bars made up of small vertical lines. After about 20 minutes they seem to stop appearing, although fragments of them remain on the desktop and dock.
It' also runs really slowly at first.

Running OS x 10.5.8
Old G5 tower
Apple Cinema display

I have tried disc utility Repair Disc (booted as a target disc) and Repair Disc Permissions

I have posted a screen grab here (it ain't pretty):
http://www.malago.co.uk/Picture2.jpg

 

[Natobasso]

Hi! Hope you don't mind, I posted your picture to my blog post on video card issues - I think you have a bad video card in your computer: http://thesalon.blogspot.com/2009/08/apple-laptop-video-card-issues-colored.html

 

[ElDiabloConCaca]

Looks like a bum graphics card to me. Solution: replace or repair the graphics card.

It could also be an improperly seated graphics card, a graphics card that has become so dusty/dirty that it's overheating, or a graphics card that is overheating/failing due to some other reason (loose heatsink, obstructed airflow inside the computer case, etc.).