Help creating and joining homegroup

Hi,

I have been trying to set up a home group in windows 7 for a couple of weeks now with no success. I am wanting to link my studio machine (Dell Xps 8100) to my new laptop (Xps 15z) to make life easier when exchanging data between both computers. My laptop is using it's built in WLAN card, my desktop using a belkin usb wireless adapter to connect to the Internet/network which is managed by a BT Business hub/fusion router.

Setting up a homegroup is easy enough, but once I have set a homegroup up I have no option to join it on my laptop only the option to create a new one. The obvious solution was that my desktop wasn't connected to the network, but it shows up on the network map and I have been able to share music via WMP and Itunes which means the two computers can and are communicating with each other. I ran through verious troubleshooting methods and the only thing that came from that was that the computers times wern't synced, so I ran through the time and date settings and made sure that the settings on each computer were identical. But I still had no luck in joining the homegroup, having looked in various places for a solution I have found nothing that has helped and now I'm stumped.

Thank You for your help and suggestions