So I guess you are using your original Xoom USB cable, and have tried different USB ports (like the ones on the back if you have a tower), you tried with debugging on and off, you've tried with the USB plugged into the Xoom 1st and then into the computer as well as the other way around...do you have Windows Media Player (9?) installed on your pc? It seems it needs it to connect....
Transformer Infinity 32Gb - JB 4.1.1
ROM: CROMI v4.4 with _that kernel
Nexus 7 32Gb - JB 4.2.2
ROM: between sparksco's sabremod and sbdags' CROMi with M-kernel
SGS2 Epic 4G Touch - JB 4.2.2
ROM: Evervolv, Baked or Magical Unicorn
Xoom WiFi - JB 4.2.1
ROM: EOS 4 Wingray Nightly 180
Rockin' TWRP Touch Recovery
--helps you, give them a THANKS!