A crucial piece of info you gave us:
I uninstalled the SP1 beta.
My experience, sad but true, is that MS has never gotten it right on installing and removing sevice packs, beta, relecase candidates.
Did you perhaps make a full image backup of your computer before intalling the beta?
My suggestion at this point is to backup all data dear to your heart, because any attempts to fix the problem may just make bad matters worse.
After doing that and trying sfc /scannow, trying a repair install, trying installiing over your present persion, I don't know what to suggest because you have lost all of your old restore points in the process of installing the beta and removing the beta. Repair Install