From The Windows Club:
Unlike in Windows XP, Windows 7 or Vista, does not include a Desktop Cleanup Wizard, which kept track of your usage of the icons on your desktop and offered to remove the unused icons every 60 days. CleanDesktop is a small portable freeware app which will help you clean up your unused desktop icons, in Windows 7 & Vista. This utility is for those who miss the wizard. On running it, it will scan & detect desktop items which have not been used in the last 30 days and and list them down. You then have an option to delete them. The unused items are not deleted but moved to a folder on the Desktop viz; C: \Users \username \Desktop \Unused Icons. Alternatively, you cans also opt to delete the unused items directly.