Reg Clean
If you set a system restore point before you run reg clean, then if it goes wrong you can get it all back, however as reg clean backs up all the files it deletes, you can put them back from within the program itself.
As to what to delete, on the main page select all entry’s that relate to programs that you have uninstalled, (Uninstall Cakewalk first) and remove them. From the tools menu choose “do all” option, and delete all that reg cleaner shows restart your computer and then install Cakewalk.
For home users 2 hrs or so with the loss of computer use is ok, but when your computer is your living, or part of a network, then 2 hrs is serious downtime, and is to be avoided if at all possible. (Administrators will know that keeping the system up and running until the working day is over is paramount, and managers get very annoyed if you don’t achieve this)
Hope this helps.

Bill