If you have a lot of temporary files in Vista, you can use the Disk Cleanup application to get rid of most of them. But this app does not delete temporary files that are less than 1 week old. If you have some fairly recent large temporary files that you want to get rid of and Disk Cleanup will not do it for you, you can get rid of the files manually. Type %TEMP% into the Start menu search box and you'll be taken to the temporary directory. You can then manually delete any of the temporary files that you want.