Hi Fred -
Go here and put in the Service tag number for your laptop: Drivers and Downloads | Dell [United States]
Download the Ethernet (wired) or Wireless LAN driver for your laptop, unzip and run it as Administrator. You should then have a list of networks accessible by left clicking on the network icon in the bottom right corner of your desktop on the task bar. If not rightclick on the same icon to run Troubleshooter.
Once you're online go to Windows updates to search for updates which should include drivers under optional Windows Updates. After all Updates are completed, any drivers still missing in Device Manager can also be imported from the Dell Downloads webpage for your tag number.
In the future follow these steps to get a perfect Clean Reinstall - Factory OEM Windows 7
then save a Windows 7 backup image so you never have to reinstall again.