1) a factory reset does not uninstall a rom it just lets you start it fresh.
2) if you did not make a nandroid back up you can install tbh
TBH & MyDroidWorld Present: Droid 2 (2.3.20) Triple Threat
that will get you back to stock rooted. If you want to go back to complete stock they have the sbf there. To run an sbf boot into the bootloader (power on + up)
this video shows the basics (before I post just to let you know that the video is meant to show you the basics....do not attempt to use the file he is using, you do not need to worry about the patch, the video is meant to show you the basics. you will use the sbf file and sbf from tbh, in fact in the video you can just start at when he gets to the bootloader.
here are the vids:
http://www.youtube.com/watch?v=CIdtdYqbasw
http://www.youtube.com/watch?v=H62KLc4kKN0