Does your receiver require you to install the drivers first before you even connect it to the PC?
I had the same problem last year when I went wireless. It turns out, if I had the device plugged in before I had used the setup disk to install the drivers, Windows would load default drivers that didn't work and would mess with the system.
This was especially a pain for me, because my receiver is a PCI card, so having to remove that everytime I reformatted Windows wasn't fun
.
Just double check your manual (or search for it on the net) and make sure your installing things in the correct order