To restore factory setting, they should have sent a set of restore discs with...
To restore factory setting, they should have sent a set of restore discs with the PC. If that is the case, read the instructions on teh CDs and use them to restore to factory settings. If you do this, you will lose all data on the computer.
Another option is checking if the wireless card driver is being loaded. Chances are that with the update, the driver may have been changed and is no longer functioning properly.
Here is a great wireless troubleshooting guide that can help you in checking if the card is not functioning due to hardware or software failure: https://help.ubuntu.com/community/WifiDocs/WirelessTroubleShootingGuide