1) Completely un-install SONAR from your computer. This is normally done from Start | Programs | Cakewalk. This will not remove any of your project files or audio data.
2) Open the Run Command
In Windows Vista and 7 this can be done by holding down the ‘windows’ key and pressing ‘r’
3) At the prompt type regedit and click OK.
***Backup your Registry before making edits - you do this by clicking the File menu, Export Registry File. ***
4) Now delete the following Registry keys:
HKEY_CURRENT_USER\Software\Cakewalk Music Software\SONAR Producer\X2
HKEY_LOCAL_MACHINE\Software\Cakewalk Music Software\SONAR Producer\X2
NOTE that this will remove any effects presets and key bindings you may have made in Cakewalk. You can back these up separately if you like, using Options|Key Bindings, Tools|SONAR Plug-in Manager, and Options|Colors. Hit F1 in these views for detailed instructions on how to do this.
5) Open the 'Run' command again.
6) Copy and paste the following into the prompt: %appdata%\Cakewalk
7) This will open your Cakewalk Application Data folder, right-click on the SONAR folder and choose rename.
8) Rename this folder SONAR X2 Backup.
9) Open the 'Run' command again and type msconfig Click OK and then click on the Startup tab at the upper right of the window that opens.
10) Uncheck all items listed, click OK, then restart your computer. You can always recheck those items again at a later time.
11) Then reinstall SONAR. Make sure to have any virus scanners disabled on installation. It is not required or recommended to turn off any windows services.