Techmunch

Windows Vista offers in-built tools for freeing up disk space. This tool can be accessed by navigating to Control Panel -> System Maintenance -> Administrative Tools -> Free up disk space

After selecting the drive and on clicking OK, the following dialog would be

displayed and then the Disk Cleanup dialog box would be launched.

Now select the files that needs to be deleted. Some of them to look for is Temporary Internet Files, Recycle Bin and Temporary Files.

If you would like clear some more space then you can go for the more options which would provide options for clearing space by removing unwanted programs or System Restore and Shadow Copies. Be careful while selecting the latter option as it would delete the shadow copies and backup images.

On selecting Cleanup button under Programs and Features, Uninstall or change a program window would be displayed through which you can remove unused programs.