Let's try this FIRST:
1- Turn off your wireless router (and unplug it from the electricity outlet if it does not have a power button) BUT PLEASE FIRST BOOKMARK THIS PAGE SO YOU CAN COME BACK WITH ME AFTER THE RESTART
2- Turn off your internet modem (if you have one) and unplug it from the electricity outlet
3- Turn off your computer(s)
4- Turn off your wireless printer(s)
5- Wait 5 minutes
6- Turn them all ON again.
7- Try to connect
4- Please click Start, then Control Panel
5- Now click "View by: Large icons"
6- Click "Network and Sharing Center"
7- Click "Connect to a Network"
8- A list of wireless networks will show up. Please select your network (it may be 'linksys', John's network, etc) and then click "Connect"