I am assuming you are on XP and the pc is not connected to a network.
First ....do you have a virus checker and a firewall? (click here for a free firewall)
Now go Start, and then click My Computer. Under Other Places, click My Network Places. Click the link for View network connections. Can you tell us how many connections you have here and their names.
Also can you please download and run the 30day free trial of The Cleaner click here just as an extra check.