Well, drat! I looked at PowerRen again and it DOESN'T have the ability to remove a given number of characters. I use a utility called 'Better File Rename' which, once installed, appears on the right click menu for any file or directory. Unfortunately, this one isn't free, but it'll do ten files at a time with the trial version and, to my knowledge, there's no time limit. Before I registered it ($14.95), I would select ALL the files I wanted to do in a batch, right-click on one, then set up the BFR parameters. It'll give you a message telling you the trial version will only do ten files. Press the enter key and ten files will be done and the program will exit, with the rest of the files still selected. Since BFR retains the parameters you set until you change them, you can do the rest of the batch by right-clicking, then hitting Enter twice (or three times, I'm not sure). A little tedious, but still better than one at a time.

This one is found here:

Better File Rename