Cross check your memory with memtest86 bootable CD
for 5-6 passes as it could mean memory problems.
Next, run sfc /scannow to check integrity of System files.
Finally the next best thing before doing a Clean Reinstall is to Repair Install
which reinstalls the OS while keeping programs, files and settings in place. However, botched settings can be transferred back in.
Others may have a more specific fix but I wanted to get you started since you've waited long enough.