3 utilities to do this are listed here:
This program works on Windows 95, 98,ME, NT, 2000, and XP. I’m not reallysure if it’s going to work on Vista ornot. I’ll see if I can find one thatdoes! Anyway, it works without anyinstallation and only needs InternetExplorer version 3 or above installedon the computer. Click Add Files,select the dates you want changed andclick Change File Dates! Prettysimple. Note: Only works on files.
This program has a prettier interfaceand allows you to multi-select from anexplorer type interface rather thanhaving to add files one by one. Youcan also change the dates of foldersusing SetFileDate. It’s very small andvery easy to use!
The difference between this programand the others is that eXpress TTallows you to change the date and timefor a file or folders AND optionallyall sub-folders. This can prove to bevery useful if you need to change thedate and time for all files andfolders under a specific folder. Youcan change the creation time, modifiedtime, and last access time.