Car: 1998 Audi A4 1.8tQ

I own full licence Vag...it used to work like clockwork with no problem. One day in oct. i got a CEL, which i'm used to getting occassionally because i have a HFC but no foulers so i get p0420 occassionally, not a problem, i would just go in and clear it. Well this illfated day, it wouldn't respond to my VAG-COM, told me that the controller didn't respond. I figured it was just a temp thing rebooted pc and tried again...same thing. Took it to autozone to see if their scanner would talk to the controller but it didn't make a connection either. The car starts and runs so i think the ecu is ok. I do have an after market cd player installed so i'm thinking its the k-wire issue. well i unplugged and took out my cd player, tried it again...no luck. checked the fuse...no luck. It's Jan and i needed to do emissions in Oct...i've been trying since oct to get this fixed. If anyone can help or Walker...teh guru so i've heard if you can help...I'm in Alpharetta.