I found a Bluetooth USB adapter and no one has claimed it. I plugged it into my pc and the pc found it and installed it ready for use. My phone is Bluetooth compatible, can I use this adapter for anything?

Short answer: Depends on the model of phone and the carrier you chose.

Many phones which can play music can have music transferred to them via Bluetooth. Transferring pictures and contact data works with many phones too. If your phone happens to be a Nokia, Nokia PC Suite is a helpful tool.

However, some carriers disable this functionality (namely Verizon) do "encourage" you to use their network (fees!!) or buy a special USB cable (expensive!!) to transfer data. (Some say "bluetooth headset capable" rather than advertising unrestricted bluetooth)

To get it working, first enable Bluetooth on your phone, and ensure its set to visible. Have your computer scan for Bluetooth devices. Once your phone shows up, request to "pair" with it. If you are prompted to enter a password, consult your phone's manual. (Often 0000 is the default) Your phone and PC should then be able to connect.

Hope this was helpful.