Hi Bill,
The Intel® Gigabit CT Desktop Adapter can support Windows* XP System with the final driver release version 18.3.
To further troubleshoot the compatibility issue, we recommend to try connecting the Gigabit CT adapter to another device.
I understand your system comes with an integrated network card, please disable it since you have installed the Gigabit CT Adapter.
We look forward to your test results.
Sincerely,
Sandy