My 1990 base model gauge cluster goes out every so often, and if I shut it off it won't start back up, but if I leet it set for a day or two or sometimes a week it might start back up, I know now that when I put the key in to unlock the door and the interior lights don't come on I know it won't start, if the interior lights do come on it will start, I don't know what to do?,is this a common problem and can it be fixxed, I've owned my car for a year and got to drive it 3 times, any suggestions would be greatly appriciated

Sounds to me like you need to have a look at the battery /  battery connections.

New battery and connections, everything cleaned, I heard that it may be a vats problem, how difficult is that?

I guess it could be a VAT problem, but that is not what it sounds like to me. But I am no expert here. To me it sounds more along the idea of a bad ground. But like I said, I know very little.

You are loosing a connection somewhere. A VATs issue would NOT keep the lights from coming on....it would simply keep the car from starting. Doublecheck the connections at the battery, and starter. Also check the ground from the battery tot he frame and engine. A loose ground on the engine or chassis/frame can do this. You might also have a fuse link that is faulty. Not sure where they would be on the '90, but there are usually at least a couple in the wiring down by the starter. I'd have to look at the wiring diagram to be sure.
Bottom line is, it certainly appears to be a bad connection.