We need more info, when you said no connection, what do you mean, no connection to the internet or no connection between the 2 pcs? For the internet, how do you normally connect? via modem or ADSL, cable, perhaps? for the latter, are you in the same workgroup, same IP and submask's range? What about sharing files and folders?
When you answer some of this questions, then we will able to help you.
Best regards
Eltano