Getting a lot of Event ID 5722 (Computer Failed to Authenticate) on all DC's

We are getting about 15-20 of these errors on each of our 2003 domain controller's.

Event Type: Error
Event Source: NETLOGON
Event Category: None
Event ID: 5722
Date: 5/17/2013
Time: 12:57:03 AM
User: N/A
Computer: NT1
Description:
The session setup from the computer WS21 failed to authenticate. The name(s) of the account(s) referenced in the security database is WS21$. The following error occurred:
Access is denied.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 22 00 00 c0 "..À

We are also occasionally getting calls from our users who are unable to login to the domain with "The trust relationship has failed" type errors. Not as many as we are getting the 5722. We have been dis-joining and re-joining these PC's with success, however the frequency of computer we have to do this with are increasing.

It may not be related but we are also getting users who are getting temporary profiles when they logon with ntdat.dat file's already in use. Logging off and back on will fix this temporarily UPH clean does not help as this occurs right after powering on the PC for the day.

These are all valid and active computer accounts so I'm not sure why this is happening. Any advice on how to troubleshoot this?

Thank you!