Is the DC that went down coming back up or are you all considering it dead and gone and not fixing it?
If dead and gone
Seize any FSMO roles off that box to DC 2
http://www.petri.co.il/seizing_fsmo_roles.htmRun a metadata cleanup of the dead DC
http://www.petri.co.il/delete_failed_dcs_from_ad.htmWas DC2 a global catalog server too (hopefull yes)
How is baracuda configured....I've heard the ads but have not used it. Does it point to DC1 by name or IP?
Another thing to really think about is to now get another DC up once this is fixed. You are dealing with old boxes and right now if your current DC dies you have a lot more work on your hands.
Thanks
Mike