Everyone has their own bag of diagnostic tricks when Windows decides to chuck a wobbly. While OS corruption isn't as big a problem as it used to be thanks to journalled file systems and tools such as System Restore, you can still be caught with your pants down by malware, viruses and other nasties. In those cases, a utility called SFCFix might get you out of trouble where other options fail.
Anyone who's done even a small amount of troubleshooting on Windows is familiar with a program called System File Checker. It's designed to scan your core system files, detect corruption and replace damaged files with working versions. Unfortunately, it can be temperamental at times — it'll let you know something is wrong, but fail at the fixing part.
It appears to work for all modern versions of Windows and even if you don't have a malfunctioning system, SFCFix might be one to add to your toolkit.
Automatic SFC Corruption repair (SFCFix.exe) [The Tech Cookbook]