[A] Create a new System Restore point:
1. Go to Start > Help and Support > "Undo changes to your computer with System Restore".
2. Click "Create A Restore Point" then click Next. Give it a name it and then click Create, then Close.
3. Close the Help and Support Center box.
[B] Clean-up your computer using the Cleanmgr utility:
1. Go to Start > Run and type "Cleanmgr"
2. Select (C: ) then click OK.
3. Click the More Options tab.
4. Click Clean Up in the System Restore Section.
This will remove all previous restore points except the newly created one.
Regards,
Nico