i had this problem, turned out my AV was blocking it, have you tried restoring from Safe Mode?
Norton is notorius for not turning off properly, even if youv disabled everything
Don't know about "Safe Mode"
when booting your PC spam F8 your pc should boot into Safe Mode.... (key may be different.... for instance on mine i have to press F5 then F8 when it loads to find Safe Mode check your documentation if these 2 dont work)
Computer type PC/Desktop System Manufacturer/Model Number Self Built OS Windows 7 Ultimate X64 SP1 CPU Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz Motherboard Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz Memory 8GB 1333Mhz DDR3 Graphics Card NVIDIA GeForce GTX 460 Sound Card Realtek Monitor(s) Displays Acer Al1980, Screen Resolution 1360*768
Keyboard Alba USB Mouse IT Works Wireless USB PSU 750W Cooler Master Case Cooler Master Haf X Cooling Cooler Master Hyper TX3 Hard Drives 500GB SATA WBC
1TB WD Caviar Green
80GB IDE Samsung Internet Speed 12Mb/s Down 1.2 Mb/s Up
I find that it is much easier to make an image of the system drive and keep it up to date rather than depend on system restore... if something does go wrong, it is a simple matter of restoring the image ...
System Manufacturer/Model Number ASUSTeK Computer INC. CM5675 OS Windows 7 Ultimate CPU Core(TM) i5 CPU 650 @ 3.20GHz Motherboard ASUSTeK Computer INC. CM5675 Memory 6.00 GB Graphics Card Intel(R) HD Graphics Sound Card Intel HD integtrated Monitor(s) Displays Samsung 24' Screen Resolution 1900/1020
Hard Drives (1) INTEL SSD SA2M120G2GC ATA Device (2) ST31000528AS ATA Device Internet Speed 30mb