In tip 0271, we described a process you could use to correct the lose of the .EXE association in the registry.
When you are up to your ___ in alligators, it is difficult to remember that your origonal objective was to drain the swamp.
Before booting to an alternate instance of Windows NT, you could try to:
1. Rename Regedit.exe to Regedit.com, as .COM is also executable.
2. Use Regedit.com to fix the problem at HKEY_CLASSES_ROOT\exefile\shell\open\command.
3. Rename Regedit.com to Regedit.exe.