Time Syncronization

All of my servers are showing the correct time (NT, Windows 2000 and Netware)but my workstations all show an hour ahead. Has anyone ever seen this before and where could the workstations be pulling this erroneous time from?? Interestingly enough, I have one computer that reboots automatically nightly and it always comes up correctly..it’s the only one. If you disconnect a computer from the network, adjust the time and reboot, it keeps the correct time but if you leave it on the network, adjust the time and reboot it jumps to an hour ahead. This is driving my users crazy and I have no clue as to where the wrong time could be coming from. HELP!