How can I make it possible. When I order it to Defragment it show up "defragmentation of the windows registry is currently not possible. Systen restart required." Then, I restart and it show the same thing. What should I do?
Do nothing if you are running Windows Vista or later versions - defragging the registry will not give you any performance benefits and was only necessary for Windows XP and earlier.
The registry was changed when Vista came out so it does not suffer bloat as previous versions of Windows did.
If you are constantly installing / uninstalling programs then you may need to clean the registry occassionally.
However running certain well known 'registry cleaners' will remove registry keys which are essential for every Magix program you have installed.
The only fix when this happens is a re-install / repair.
Personally I avoid using any 3rd party cleaners / tuners / defraggers as much as possible, The only cleaner and defragger needed is already installed with Windows.