Wow! Have not heard of a Fastec user in many years. I would do as I mentioned earlier just load Win 95, if needed, you can get clean Win 95 disks. Win 98 could be problematic and never heard of an NT OS working with Micros 2700 software.
One thing I would not spend time doing is using a brand new mobo from 2008 and loading 95, 98 or NT.
If you are that committed to Fastec and desire reliability; buy, beg, borrow an old PC, they're very easy to come by if you know where to look. Find two, just in case. Install new power supply's ($40), dual hard drives, even an old HP Colorado 5Gb Tape drive unit ($40) for backup. Ultimately, I think that will be the least complicated and best approach. Good Luck!