NewFileTime is a tiny and portable tool which can help you change the created, last modified and last accessed dates of your chosen files and folders.
Selecting particular files and folders is as easy as dragging and dropping them in from Explorer. (Although there's also an "Import" option, if you need it, which allows you to browse the file system as necessary.)
By default NewFileTime opens with its "Set time" option selected, and the created, last modified and accessed time all set to the program's launch time. If you're happy with that, click "Set-Time" and the dates will be changed right away.
There are also options to "be older" and "be younger", which will modify the date by a specified number of days.And there's a menu where, again, you can set the new date and time in a couple of clicks.
NewFileTime is a little quirky, in places. Calling the Browse function "Import", for instance, means most people won't immediately be sure what it is. And why do you have to click a # symbol to launch a menu?
There are plenty of features here, though - far more than we have any right to expect from a 56KB application. And it doesn't take that long to figure out how things work, so if you need to tweak your file or folder times occasionally then NewFileTime could be ideal.