Windows 7, After Restore Point, The trust relationship between this workstation and the primary domain failed
Every client has a computer account which is in sync with the Domain Controller. If the computer account is too old (Like on VMWARE Snapshots) and does not match the one on the DC you fail to logon with the computer account. One of my developer machines is a Member of a Server 2003 R2 Domain.
After installation an Acronis 10 WS i had a horrible error with the SNAPMAN Plugin again. And not this time i could not recover even with the long KB from Acronis. So i went back to a restore point... I hate that and normaly i never have done it.
Well gues what if the "Restore point" is a certain amount of days old the Computer can't sync/Log on to the DC: That's somehow correct and usefull in terms of security but MS should warn user. Hopefully you have the local Admin password to acces the client. Otherwise you will have to use Hiren or some other boot CD to reset the Windows 7 SP1 admin password.
Disjoin/Rejoin the Domain and you are back in the game.
Please read both: