Reinstalling error

[Adarne94]

When I try to reinstall Windows 7 I get an error saying ''the instruction at 0x12f9b5b7 referenced memory at 0x0000001. The memory could not be read''. For some reason i'm also not able to access certain files even though i'm an administrator and have been getting programs not responding a lot and freezes and some BSOD's. I ran memtest for 7 hours but I got no errors and I cleaned my registry. Please help