OEM version of NT 4.0 Expires

I installed the OEM version of Windows NT 4.0 on 7 P.C.’s. The version however, has expired like an eval copy. My 3 boot disks were made from an eval copy of NT 4.0 workstation so I think I know the cause, but I don’t know of a workaround without re-installing. If anyone knows of one please let me know.

Thanks for your help.