My guess is that you're using some custom screen templates. There are dealerships out there that use them as part of their default setup, so you may not even know about it.
The ETC folder contains any custom scripts, SIMS, templates, etc... that are used by POS operations. These are copied to the workstations through CAL. Most locations aren't using full XP computers, (or eclipses), anymore so dealerships aren't always setting up the CAL folder that loads them.
Go to the CAL folder on your server for the type of workstation you have:
\Micros\Res\CAL\(WS5 or WS5A)\Files\CF\Micros\ETC
You'll have some files in there. OpsDisplayUser.cfg is the one you're looking for, but copy everything in there and paste it all into \MICROS\Res\CAL\Win32\Files\Micros\Res\Pos\Etc
Reboot your computer and see if OPS loads correctly. It may or may not, CAL was always kind of flaky with Win32 clients. If it doesn't work rerun CAL and see if that does the trick.