Question : Suddenly cannot access network resources on Win 2003 server

Our network setup is as follows: 1 Win2003 Sm. Bus. Server & 6 PCs running Win XP Service Pack 2.  Everything has been fine up until last Thursday.  1 out of the 6 PCs can no longer access any network resources on the Win 2003 server.  The other 5 PCs are working fine.  The user can login to the domain.  When they get to the desktop, their network drives are not able to be browsed.  The following error message is displayed, ": is not accessible.  The system detected a possible attempt to compromise security.  Please ensure that you can contact the server that authenticated you."  There is nothing different about this user account on the Win2003 server, or anything about the network settings.  I ran Ad-Aware & Spybot and there were no threats.  Anti-Virus also says no viruses.  The only way I can get the network access back is to do as follows on the PC whenever it is rebooted: Go to services.msc & stop the workstation service (which also stops net logon and computer browser services).  Then I restart all 3 of those services.  Then I go to My Network Places & make sure I can browse the folders on the win2003 server that the user needs to access.  Once I have completed these steps, the user can now access their network shares.  I am stumped as to why this all of a sudden is occurring and it is only affecting this one PC.  Does anyone have suggestions on this one?  Thank you in advance.

Answer : Suddenly cannot access network resources on Win 2003 server

I did finally figure it out.  Here's what I did:
Backed up the user's directory on the PC (C:\D&S\username) to an external source.  Then I logged in to the PC with the domain admin login.  I removed the user's account completely from the PC.  Then I restarted the PC & logged in again as the domain admin.  I re-added the user from scratch to the PC as a power user.  Logged off as domain admin and logged in as the new user's account.  I restored any necessary DATA/SETTINGS ONLY from the directory I backed up at the beginning.  
I had tried something similar to this previously & it didn't work.  The difference was that the first time I tried this, I was logged in as the PC admin, not the domain admin.  And, the first time I tried it, I didn't delete the user's directory prior to removing the user's account and re-adding it.
I knew it wasn't something on the DC because I added that user's account on other PCs and used the account with no problem.  I also had tried adding other user accounts to the problem PC and they also worked with no problem.  My conclusion is that there was something corrupted in the user's directory on the PC within Docs & Settings.  This all began right after the windows update was auto installed around April 10th.