Sound buzzes after lightning storm, replaced soundcard, no change

After a lightning storm that knocked out my landline phones, my printer, which was connected to phone lines for faxing, and left my sound buzzing, I have not been able to resolve my sound problem. I had to replace the printer entirely, and hooked up the new one which works no problem. Unfortunately, after trying to replace the sound capability with a new sound card, I still get a buzz, and the computer does not recognize the new hardware, as I do not get an installation wizard prompt after I secured the card in the bay.

I turned off the onboard sound in the bios. No help. Installed the software anyway. No difference.

Am resigned to what my tech friends have suggested - that I will have to replace the motherboard. If the new printer installed fine, why is the sound not so easily resolved? Will just buy the motherboard if there is no other solution besides what I have already unsuccessfully tried. If I've missed something, can anyone suggest the next step? I don't want to replace the motherboard if it's not necessary. Thanks.