As we can't get any logs from your system, we have to consider a lot of eventualities.
What the error means is basically windows is in the process of checking if every hardware component works as intended, obviously it's not in your case and windows should proceed to repair any glitches but fails miserably at it, as usual.
Still could be a lot of things, even if a roasted GPU makes sense in your case, it could just be some bad sectors on the HDD who screwed up the classpnp.sys.
There's some workarounds.
1) Run sfc/scannow from your win7 dvd
http://www.sevenforums.com/tutorials...ompt-boot.html
2) Load failsafe defaults/reset bios.
3) Get the classpnp.sys from your exact OS version from a really trusted source. Just use another computer or have a trustworthy contact send it to you. Do not download it from anywhere.
Get
www.knoppix.org , burn it to a DVD and boot a fully functional, live version of Linux to replace the files in windows. (It's really easy, NTFS drives are auto-mounted with one click)
You can also use it to access your HDD and make backups to a dvd/thumb drive prior to reinstalling windows.
In case you know your way around linux a little you can also use it to detect and troubleshoot any hardware issues.
4) Reinstall windows