This is in reference to the REGENV32.EXE
During Shut the Registry needs to locate the Msconfig settings and cannot

I found most computers with this problem Had:

Tweak95 installed
Tweaked the desktop and my documents etc.. to a new location

Msconfig was edited (Microsoft Configuration Editor)
Autoexec.bat and Config.sys files Cannot be found by Msconfig

Reinstall Me
or
Repair can be done in the Registry and Tweak

If You must reinstall the OS
Format with the UnConditional command
C : / U
The system and hidden files can be cross linked and all will be removed
The Debug Command will work but low level format is safe.