System time not staying in sync

Also noted that we are in an enterprise environment and he is the only user experiencing this problem.  Virus software used is symantec.

configure to sync with a time server
http://support.microsoft.com/kb/314054

Do you have the time zone set correctly?  

Yes it is set to the correct time zone.  Sorry for leaving that important part out.

If this workstation on a domain? If not, does it have access to the Internet? If it's on a domain, it should be synching automatically with the domain controller that holds the PDC emulator role.  If that's not happening, and only on this workstation, I would advise unjoining and rejoining the domain to refresh the workstation's trust relationship with the domain controllers.
If the workstation isn't on a domain but has access to the Internet, you should check to be sure it's set to synchronize it's time automatically with an external time source.  This can be set by entering the following at the command line:
net time /setsntp: time.windows.com, 0x1
Then stop and restart the W32time service, either from the command line or Services console.

This computer is part of a domain.  Our head network admin told me to do the exact same thing as your suggested hypercat,  we have tried your exact instructions above several times actually, however we are still not able to get the clock to stay in sync.  

Flyingsky.... going to try then will post back.

How long these "ahead and behind"?

The time always varies.  It is never by the exact same time increments.  For example, two days ago when I looked at his machine, it was 50 minutes ahead.  Yesterday it was 5 minutes behind.  Its always a different time but its really weird because it just both forward and behind.

I had the same experience with low CMOS battery but as you said it's not your case. Replace entire PC. :)

<<Our head network admin told me to do the exact same thing as your suggested hypercat,  we have tried your exact instructions above several times actually, however we are still not able to get the clock to stay in sync.
LOL - apparently great minds think alike even when they're dead wrong!
This is quite puzzling.  It sounds like there's some application or malware/spyware running on this thing that is causing this to happen. Malware/spyware is still possible, even if you reimaged the machine, IF the user has a roaming profile. The malware/spyware could have hidden in his profile and taken effect again when he/she logged on again. If that might be the case, I'd advise wiping and re-imaging the machine and at the same time deleting the user's roaming profile and creating a clean one.
If not - What other applications are running on the workstation - anything different/unusual compared to what others on the network are running?

I went ahead and replaced his machine.  Still going to give it a few days before I post back.  Really odd problem that I have never seen before.  And To answer your question hypercat, we do not have roaming profiles for our users and all of our images our deployed from a pre-built ghosted image.  

Ok so we have now got the problem to duplicate after replacing his machine. Yep, his system time still jumps ahead/back by undetermined time increments almost daily.   We replaced the cabling in the closet and are waiting to see the results but the only constant now is our customer.  Any other ideas guys?  Thanks!

Turns out that the cat5 was the older cabling that we no longer use and since we replaced it, he no longer has time sync issues.  The cables replaced were in out network closet from panel to switch.  Thanks for all your input.