The Multiport wireless card is probably what? Wireless B only?
IF so you may just want to replace it for a newer better standard. G is newer, faster, better range and replaced the B, and N replaces the G with the same upgrades, faster more range etc.
Now if you dont want to replace....Some things to try, it is installed in the multiport? If so that is on top of the LCD screen, usually the silver part towards the right. It is usually held down by one tiny screw. Unscrew it....make sure the connectors on the LCD side and the Multiport side contacts are clean...and clear from dust debri etc...then reset and screw back down. Try it again...? Make sure that it is also enabled...? Usually by pressing the Function key and something like F2...(not sure...depends on the make and model.) So you may have to consult your manual...or look at your F-Keys....to see which one it would be.
According to a few sites it should be FN+F2...meaning hold down the function butting and PRESS the F2 button then let go. That should do it. See if the system then see's the card....
If the device manager shows the wireless card and it still doesnt work, you might try reinstalling the drivers.
Otherwise maybe time to upgrade and install a new PCMCIA Wireless G or N Card. However you may need to get a router that supports those connections. If you travel, with a G or N card you may have better access at hotels truck stops and hot spots....
So something to think about as well.