i have never used citrix so not sure but looks like you have some serious problems their can you even open AD can clients login OK ? what i would check for is to make sure that my group policy is all correct you should really only have the minimal applied e.g password policy etc but i would also make sure that their is no firewalls turn on you shouldn't have them on any way all servers are static ip address which I'm guessing they are also you want to make sure that in your root dns servers that you have the correct srv and pointer records and also that the ldap.TCP is correct the zone transfers are correct your scavaging scale are setup properly and i would also check the last time the system replicated to and from other servers also think back to the last thing that happen before all this went wrong try and trace your steps did you applied any service packs or anything like that or did any one change any passwords that used to authenticate anything also ask your team
