Look into doing something like this:
http://csg.trinhall.cam.ac.uk/tips/ntp/winxp
...and you won't have to manually sync your system's clock any more. Additionally, because this solution uses network time protocol (NTP), your clock should stay synced much closer than a second to the atomic clock.
This is a common gotcha when using FIX, and using NTP is certainly the recommended solution.