After using your computer for a long period of time (over a year or so) it’s probably safe to free up some space on your hard drive by deleting all but the most recent system restore checkpoints (file shadows) and complete PC backup images (if supported by your version of Windows Vista).

Warning: Before removing all but the most recent system restore checkpoints and complete PC backup images make sure you will never need them again. Once you remove them, you can’t get them back.

1. Click the Start orb, All Programs, Accessories, System Tools, and open Disk Cleanup.
2. Click Files from all users on this computer.

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3. Wait for System Cleanup to calculate how much space it can clean up. This could take some time.
4. Click the More Options tab in the Disk Cleanup window.
5. Click Clean up under System Restore and Shadow Copies.

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6. If you’re absolutely sure you want to delete all but the most recent system restore checkpoints and complete PC backups click Delete.

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7. Click OK in the Disk Cleanup window to close it. Disk cleanup will clean up files checked off in the Disk Cleanup tab before closing.