Computer won't recognize calc after flash ROM reset

[fackert]

A few weeks ago I was cleaning up my TI 89 and I must have deleted the wrong thing. I think I reset the Flash ROM. Now I when I try to connect the calculator to my computer it doesn't recognize it at all. I know the connection is good because when I plug the cable in the calculator powers up. Also I've been able to transfer data (files and apps) from my friend's 89 to my 89. What can I do so my computer recognizes it???? I don't believe it's a problem with my computer because my friend's computer doesn't recognize it either, and it was working perfectly before I reset the flash ROM.