So im using ruby on rails in windows (i hear you all spitting your coffee onto the screen), its only a short term thing. (using ubuntu at home) So i tried to fire up webric
Try using netstat -a -o -n to determine the pid of the process running on port 3000. Then you should be able to use taskkill /pid #### to kill whatever process is running on that port.
Probably not the most graceful way to do it, but I think it should work.
EDIT
You'll probably have to also use the /F flag to force-kill the process. I just tried it on my local machine, and that worked fine.
Go into rails_project\tmp\pids and delete the .pid file in there.
run:
rails server