I have a abu garcia silver max i used it all summer fine and i used it for the first time today since last year and the anti reverse is going out and the spool is going backwards. what could have caused this or what can i do to fix it?

Pull the reel apart, and clean up the anti reverse clutch bearing in the handle side plate

It may just be dirty. If it's like the Revos the AR is press fit into the side case. The case needs to come off and you can spray the AR out with carb cleaner or similar solvent. Let it dry and oil it lightly with a cotton swab. The AR collar should be checked for damage as well. If the AR is damaged you'll need a new side plate from ABU. This will require a fairly indepth disassembly so if you're unsure send it in and I'll through the whole thing.

As for what caused the problem, it's impossible to say without an inspection.

Abu reels are warranteed for one year. I would call them and see if it's covered.