I recently started model editing and found that creating new adts required renaming a bunch of files. This is a program that I found extremely helpful it will let you mass rename files.
Here is the link: JoeJoe's freeware utilities - [Rename Master]
It isn't hard to use just start it up and select the directory that you wish to rename the files in and then select the scripting tab and hit new step, then select replace name/phrase.