Logon type 3 - ID 529

I’m in need of some urgent help. I’m running SBS 2003 with few client workstations including Xp as well as Vista computers. Since past few hours, for the first time, I received about 80 failed security login alerts from 3 of the Vista based computers. Surprisingly, 1 out of these 3 computers was shutdown for the entire day today, then how I got the alert from that system?

Here is the complete error detail:
Event ID: 529
Logon Failure:
Reason: Uknown user name or bad password
Domain: companydomain
Logon Type: 3
Logon Process: NtLmSsp
Authentication Package: NTLM
Workstation Name: VISTAMACHINE

All other fields are blank including 'User Name'

Please provide your advices. Thank you.

First of all check the workstations from where you received the alert. See if there is any app/security/system logs corresponding to the same time as the server log? Also I would like to know whether those Vista systems are running with Service Pack 1?

Thanks for your help Maratha. I checked those workstations, there is nothing in the log. Also there is no service pack installed on any of these Vista systems. Only thing I noticed at the same time as an alert this morning was:

The time provider NtpClient is currently receiving valid data from server.domain.local (ntp.d|0.0.0.0:123->serverip:123).

Is it harmful

Most probably I think the problem would occurred if those machines’ password is not properly sync. I think you need to go through the following steps to reset domain controller username and password:

ETDOM RESETPWD /Server:ServerName /UsedD:Administrator /PasswordD:*

After that, please restart the server.