If you want Windows to "forget" a driver that was previously installed you need to remove the .INF file. Under NT 3.51 they are located in SYSTEM32 (unlike newer Windows that has an INF directory). I don't know what the file will be called but it should be a copy of the .INF from the Xircom disk.

Thanks for your suggestion. I was unable to find any INF that has Xircom in the title. I've attached a listing of the INF files from /System32.

I've also attached a screenshot of what the Network Setup looks like when selecting a new adapter. There are two Xircom Pocket Ethernet III listings, but both of them ask me for the Xircom Setup Disk. Actually, when I first Add for either of the Xircom Pocket Ethernet III listings, Setup asks me for the NT Disc, but immediately after I hit OK to use the NT setup disc, it asks for the Xircom setup disk files. It doesn't even try to take the files from the CD-ROM. Refer to the attachments.

I have tested the Xircom Pocket Ethernet III in Windows 95c on my 486 using the Xircom disk drivers. This Xircom LPT-to-Ethernet adapter works.

Using LAN Speed test (20 MB file) to benchmark the adapter, going to my Opteron 185 system, I get:

Xircom to Opteron
Write: 2.1 mbps
Read: 6.8 mbps

Also, using the Intel Ethernet Express 10/100 ISA card on the same system, I get:

Intel ISA to Opteron (Win95c)
Write: 11.9 mbps
Read: 6.5 mbps

Same as above, but using NT4 instead of Win95c.

Intel ISA to Opteron (WinNT 4.0)
Write: 17 mbps
Read: 7.1 mbps

I also tried to use the Win95c default drivers for the Xircom, but they did not work. I needed to use the Xircom disk drivers to get the unit working. I'm guessing the same is true of using the Xircom in NT 3.51, so... I'm stuck at:

1STOP
2Unable to create Services subkey in Registry
3and
4Unable to access Services subkey in Registry

Thanks for your suggestion. I was unable to find any INF that has Xircom in the title. I've attached a listing of the INF files from /System32.

You have to look at the contents of the file in a text editor or compare the size/date with the original file from the Xircom disk. It looks like Windows renames the .INF for network adaptors to OEMNAD?.INF so it's probably one of these files

1oemnad0.inf
2oemnad1.inf
3oemnad2.inf
4oemnad3.inf
5oemnad4.inf
6oemnad5.inf
7oemnad6.inf
8oemnad7.inf
9oemnad8.inf

To get to the bottom of that error about creating a registry key, it would also be helpful to look inside the .INF file. See what key it's trying to create and for what purpose, and maybe test whether you can create it manually with the registry editor.

Thanks for the suggestion. I'm afraid that I'm not familiar enough with programming for inf files to locate the afflicting part of the script. Perhaps someone who comes across this thread with a similar program can follow your advice there. I've attached the Xircom OEMSETNT.inf file, renamed to *.txt so it can be uploaded.

I was able to locate which files in /system32 are the Xircom oemsetnt.inf files, they are OEMNAD7.inf and OEMNAD8.inf. Do I only need to delete these files?

Thanks for the suggestion. I'm afraid that I'm not familiar enough with programming for inf files to locate the afflicting part of the script. Perhaps someone who comes across this thread with a similar program can follow your advice there. I've attached the Xircom OEMSETNT.inf file, renamed to *.txt so it can be uploaded.

It is indeed pretty confusing. The .INF for a network adaptor looks very different from most other ones, and I don't see that the text of the error message appears in there anywhere. (Plus the names of registry keys are only referred to indirectly with variables)

I was able to locate which files in /system32 are the Xircom oemsetnt.inf files, they are OEMNAD7.inf and OEMNAD8.inf. Do I only need to delete these files?

Yes.

I did look thru the inf file for the error string, but also didn't find out. I'm giving up on NT 3.51 + LAN + NexGen for now. I'll have to be content with Win95c + LAN + NexGen, with the NT 3.51 partition being LAN-less. The two partitions cannot see each other (FAT32 and NTFS), so my only means of transfering large files is LS-120 SuperDisk. The CD-ROM on the NexGen cannot read CD-RW, so, SuperDisk it has to be.