Please help need to Sign back on to my internet connection

MY husband uses a PC with A Belkin F5d7000 wireless network card. normally the network is on all the time but he got, a warning sign on the Norton antivirus, virus definitions are out of date but he is not very aufait with things and just rebooted. Apparently there was another warning too but he cannot remember what it was. Now our internet connection on there is not working, and I cannot find the screen to re-enter our network password. I have been through Network Connections

tried repairing but am not able to do that. message comes up Windows cannot configure this connection, use other software to set it. If you wish to use windows go to WFC(?) then it directs me to the website
Later next day.....
I now have 50% signal strength, the Belkin icon in system tray is red. I am being asked to login but I don't know how to get to the login screen[ see above] to enter my network password to connect.
This seems to be happening frequently so as soon as I find this bit of information I will record it carefully.
thank goodness for my MAC which is in a different location.

Can anyone suggest what to do. I have a horrible suspicion that there may be a virus or trojan despite the firewalls as when I was installing the wireless card I was having problems and turned off the firewall temporarily and forgot to turn it back on until the next day. But I was hoping the D-Link ethernet router modem DSL300T had a firewall as a first line of defence.
Please can anyone advise on any of these points.
I am sorry if it seems such a muddle.

running windows XPhome, on 2.3 mhz emachine.