Tested new machine in Lab B this PM. It's a dual-boot, with Server 2003/2000 and Sanako apps installed. Went through 3 reboots and a series of logins/outs in both OS's and everything seems to be OK. I'm tentatively calling this a H/W problem.
Martin has suggested that I get a serial port card and try that. I might do it, as long as I can get a half-height card and it comes with it's own drivers, after what WO told me about new OS's and old tech.