There are many things that can happen with computers, but this may just help someone, even if its just in a long list of things that you try, to get your PC working again.
If your computer’s BIOS has been reset (bad battery or manually done) then all the sudden windows won’t load. In my case it was with Windows 7, and it would load the moving windows logo for a sec then freeze, same spot every time. If you try boot into safe mode then it restarts the PC at classpnp.sys.
What you need to do is this
1) Load into the BIOS
2) Change your hard disk mode. It will either be IDE or AHCI, just change it to the other one (ie, if its IDE, then change to AHCI.)
3) Save BIOS changes and restart the computer, if that was your problem it will boot into windows no problem.