Very simple. Unrar and run.
Input Old Window Title: Enter a few of the first characters of the window you want to change.
Input New Window Title: Enter the name you wish to change the window title to.
Click on "Change Title" to change the window's title after entering all your stuff into the inputs.
The Generate Title button is disabled, may make it randomly generate a window title in the future.
Be warned! This only changes your window's title. It does not change the process name or PID.
For example... run WordPad... enter "Document" into the old title. Enter "New Dox" into the new title. Click on Change Title. Blam! Window title is now "New Dox", but... do SHIFT-ALT-DEL and look at your processes... WordPad.exe is still in the process list. So you'd have to rename your .exe (I think) to change that.
anyhow... here ya go... not sure who else would want it, but try it out.