Windows 7 stuck on CLASSPNP.SYS
It's likely that the file was in use during shutdown, causing it to become corrupt. If that's the case, then the fix would be to repair this and any other corrupted files.
First, you'll have to get to a command prompt. Can you boot into safe mode w/ command prompt?
If so, use SFC (System File Checker) to fix. Once you get to a command prompt, type:
sfc.exe /scannow
Source: Microsoft Technet - Using System File Checker to Fix Issues