A little more info might enable a more precise answer.
1. Are you able to manually connect after you logon?
2. Is your connection setup as a HOMEGROUP?
3. Version of Win7, brand/model of wireless router?
1. can you connect via cable to the router, i.e., can you enter the administrative page of the modem via ethernet cable?
2. were you able to connect wirelessly at any time before, or is this a brand new setup and it never happened?
3. can you give more details as to what stage are you in now, if you need more help?