DirDate is a command line tool that can easily be automated to change files' last modification date, creation date or last access date. It can change dates using either a reference file (where you can 'lift' the date from an existing file), the current date/time or a series of YEAR, MONTH, DAY, HOUR, MIN, SEC and MSEC commands. It can process files in subfolders, and it has a preview mode so that you can see which files will be modified. You can set file date and times right down to the 0.1 microseconds (100 nanosecond increments), or even tweak existing times up and down.
Simple example - set all file creation dates to Christmas day:
dirdate -CREATION date=12/25/2000 time=12:00:00 *.*
Simple example 2 - add 10 minutes to file modification dates:
dirdate -MODIFIED ADD 6000000000 *.*
Very complex example - use the following DOS .BAT command to alter the creation date of all .WAV files on drive X: to the creation date of a correspondingly-named .WMA reference file.
FOR %%A IN (x:\*.wav) DO dirdate -CREATION filec=x:\%%~nA.WMA x:\%%~nA.wav
DirDate also comes with a 16-bit version for DOS and Windows 3.1, which can be used to change folder, volume label and file entry dates, file sizes and attributes under Windows 3.1 and DOS using direct disk writes, and it is the only application that can change DOS folder dates using direct disk writes.