Running Windows XP Pro SP2, fully updated, automatic synchronization with an
Internet time server fails. This used to work! And still does on several
other similar XP systems on the same network behind the same routers. I've
tried several time servers... time.windows.com, time.nist.gov (pings OK), et
al. I've checked that network connection and firewall settings are OK. Per
forum suggestions & KB articles, I've tried starting/stopping the time
service, ie, starting/stopping w32time, unregistering/registering w32tm.exe;
got messages indicating the opperations worked OK, but this did not fix the
problem.

The only event log message (other than acknowledgements that the time
service was successfully sent a start control & that it successfully entered
the running state) reads... "The time service has not been able to
synchronize the sytem time for 49152 seconds because none of the time
providers has been able to provide a useable time stamp. The system clock is
unsynchronized." Following the "more information" link for this event
(Source=W32Time, EventID=36), I get the less than helpful recommended
solution that time sync is "not needed" in Windows XP!

One questionably authoritative forum discussion had several users suggesting
that a recent change to a new video board has caused this kind of problem. I
find this highly unlikely! However...I HAVE recently changed to an ATI
Radeon 9550...but I didn't notice if time sync was working before or stopped
after my install. Again, I don't really suspect this as the problem...it's
hard to imagine any believable cause and effect mechanism that would link the
video board with the time sync problem.

I HAVE checked KB216734 "How to Configure A Time Server in Windows 2000", et
al, no help there. Any suggestions?