While your desktop PCI netcard is electronically connected - lights on - it means little as you have seen.
Have you changed cables? Changed ports on the DSL Modem? Try both...
Your PCI netcard is not communicating with the DSL Modem - obviously as you lack of IP addresses. The DSL Modem issues the address to the PC. So - the driver is not working
As for the CMOS Setup - any number of computers would not have a BIOS that would have such a setting.
Have you removed the driver for the old card from the device manager?
Is the card fully inserted ‘seated’ in the PCI slot? Can’t be jack up on one end - Make sure you try different slots.
Removed the driver for the new card - reboot and see if you get a prompt to install it again. If not used Control Panel ‘Add Hardware’
Download a newer driver from the manufacturer if there is one - or just another copy of the one you have - maybe the driver is corrupted.
Thanks so much for your suggestions. I’ll play with it over the weekend. Thanks again!