Lines Across Screen (No Fault with LCD)

[sochrisash]

So my iMac (Late 06 intel model) has recently been developing these lines across the screen (as shown in screen shots)

When I sleep the iMac they disappear whats going on!?

 

[Scarrus]

Very probably the Video Card frying up. Logic board replacement is the only way to fix this. I'd say get a new one if you can afford it as the logic board replacement costs half as much and is not worth it IMO.