I've got a Win 7 x64 machine that locked up on me a couple days ago. I ignored it, turned it off and back on, used it for several hours without any problems. . Got home from work that day and was locked up again. Ignoring it again, turned it off and back on, and this time it will get to the Windows login screen successfully. After I try logging in it transitions to "Welcome" with the spinning circle to the left and that's are far as we go. Tried booting into safe mode and it hangs at c:\win\sys32\classpnp.sys. Hit F8 after power cycle and chose "Repair Computer". Tried Startup Repair (found no problems), tried System Restore (errors before completion), opened command prompt and tried sfc /scannow (says a startup repair is in progress, please restart then try sfc again). Also ran mfg diagnostics on hdd just in case (passed both DST and long tests). Reinstalling isn't out of the question but it'd be nice to know how to fix this without reinstalling if possible. Thanks in advance.