Attached is a little program that does what you are looking for.
This little tool is the work of many authors across the internet. I have some listed in the program and not some. My appologies.
You can use this program to change a file's Created/Last Modified/Last Access date/time. Please use it for a good purpose and don't use it to back date a file so you don't get in trouble from your boss.
Remove "z" from the file name to hide the ugly default Access window.
EZfriend.