Okay, I spent the better part of half a day and got the WMP54G working under Windows 7 64 bit. Why Linksys/Cisco won't update their drivers is beyond me as they are readily available from the OEM Ralink (available since August!!).
I have v4.1 of the card which uses the RT256x chipset. If you have another version of the card, you may have to search to find out what version of Ralink's chipset it is using or do a little try and die until you get it. Here' is the link to the Ralink support page with all the drivers: Ralink corp.
1. From the link given above, find your chipset (under part number column) and then click to download. In the case of my v4.1, it is the one listed as PCI/mPCI/CB (RT256x/RT266x). As stated before, do a Google to find your chipset (no identifiers on the card
). Obviously throw on a flash drive if you are downloading from another computer.
2. The download is an installer. Run it and make sure to choose the option to JUST INSTALL THE DRIVERS.
3. Now go into the Device Manager and find the Network Card (should be flagged under Network Adapters since the driver hasn't been found yet by Windows). If you don't have the network card installed yet, install it then look for it. If you have it installed and you can't find it, you may have already associated it with another driver and it is not working. Find it in the list of devices and uninstall it.
4. Right click on the Network Card in Device Manager and select Update Driver Software...
5. Select - Browse My Computer for driver software
6. Select - Let me pick from a list of device drivers on my computer
7. Select - Network Adapters if not listed yet
8. Select - Ralink from the manufacturers on the left (note mine had 2 and it was the first one for me which had the a/b/g drivers the 2nd has the n nic drivers)
9. Select - 802.11G WIRELESS PCI ADAPTER
Should install and work like a charm. Good luck and I hope I saved you from going out and spending another $40-50 on a comparable wireless pci nic.
- Skinny Pirate (Captain Morgan and Diet Coke