Screen has a screen overlay, what is the problem?

On my Macbook Pro, early 2008, running Leopard 10.5.8, all of a sudden, my screen started shifting into an overlay of a screen mesh. Then a double screen mesh, sometimes with yellow color and one time, it circled through the 4 primary colors. Words are broken, everything is broken up when you look at it, and I have to +++ whatever is on the desktop 3 or more times to read anything clearly. I absolutely cannot work on photos, video, anything like that.

The computer has become almost impossible to use like this.

At first, (5 days ago) it would switch back and forth to normal, but since yesterday, the computer starts up in screen overlayand doesn't switch back, at all.

I called Apple india, as I am currently in India, but they have no answers except maybe its the logic board, and to take it to a service provider and, of course they are trying to convince me to buy a new computer. ( In India, they cannot 'repair', they can only 'replace' anything wrong. I think it is only the screen problem, because when I 'print' out anything, it prints normal. Also, so far, there doesn't seem to be any problems with my files or applications.

Has anyone had this problem? Does anyone know anything about this?? Can this be some 'maleware' problem or something else that may be seepiing into Apple OS now???

When I travel to a service place, I would really like to come with some prior knowledge or information so as to not get fooled into having to buy new when it is not needed.

Thank you in advance for any help with this.