NT Stations can’t log on to Domain

I have a PDC and BDC. Both are working fine.
I have 24 more computers that have joined the domain. All are NTFS, All are able to LOG on Locally, All are able to access this computer from a network. I have all roaming users in Domain Users and giventhem all the rights possible.
I get them all working and able to log on one day… or so I think. The next, the same users are not able to. I get them trying and I end up with account.ooo, 001, etc. It is almost like the Stations aren’t really on the domain, even though the server manager says so. I can connect to each one through network neighborhood.What could I do to solve this INTERMITTANT problem?

Thanks
Merv
mervt@arctic.ca