A. This is not actually a Regclean problem but rather just an association problem between .reg files and regedit.exe. To resolve perform the following:Use the following steps to correct this problem:
- Start Explorer
- From the Tools menu select 'Folder Options'
- Select the 'File Types' tab
- Find "REG Registration Entries" and select it
- Click Advanced
- Under Actions select 'open' and click Edit
- Change to:
and click OK
- Click OK to all dialogs
You should now be able to run the undo file by double clicking on it.