Coloured lines appear when editing an image

Hi,

I've owned a copy of photoshop CS 8.0 for several months. In the last week whenever I have opened a file and tried to edit it, coloured bars appear randomly all over the image and these change when zooming in or out, they also imprint themselves onto any documents I attempt to save. It's as if I was using some kind of trial version that has expired, though I'm obviously not.

I'm at a stage with the project I am doing where I've hit a standstill being unable to find out the cause of the problem or complete my work. Had a look on the forum but don't seem to be able to find any info on it. Anyone else know what this problem is or experienced similar? Any help would be greatly appreciated.

My experience (and I admit is was with PS 6 and 7) is that this happens when you either have 1)not enough RAM, 2)not enough free disk space or 3)a defective cable (if you are using external drives)

Most likely causes of things like that: bad RAM or a bad disk. (and next is bad CPU)

Low RAM or low disk space shouldn't cause it.