This solution worked for my XPS 1647 but I had to download the win 7 drivers for the wireless bluetooth 370 card. I went into the Win64 folder and right-clicked on the Inst file and followed the instructions. Then, I had to get the Win 8 drivers from the Widcomm site.
I made the mistake of un-installing the Widcomm software before I upgraded to Win 8. I probably could have just updated the software from Widcomm instead of re-installing win 7 version.