I have a AMD A8-6500 APU Processor (4 Core 3.5 GhZ) on my hp pc . When I first bought it it ran everything amazingly , but about a month later it isn't running as well as it used to. I don't think its any programs I've installed , I tried system restore and it says "A required drive partition is missing" I don't have any files I need to keep. PLEASE HELP P.S I have Windows 8