Google Desktop History

Whatever you search using the Google Desktop is saved. You can clear them by following these steps:

1. Close the Google Desktop Software
2. And open the folder
C:\Documents and Settings\username\Local Settings\application data\Google\Google\some alphanumeric code (12 digits) << for Windows XP and
C:\Users\username\AppData\Local\Google\Google Desktop\some alphanumeric code (12 digits) for Windows Vista
3. Delete all files you can see there except files that start with sidebar_

4. Restart Google Desktop Search.