How to install the Linksys WMP54G PCI Wireless card on Vista 64
Guide is only tested with hardware version 4.1

Download the driver from the chipset maker (Ralink)

Ralinktech Website RT2500 is the driver you are looking for
Direct Link

Inside of Device Manager, there should be a Network Controller with a yellow ! symbol.

Double click that, and then click Update Driver

Select Browse my computer for driver software

At the bottom, select “Let me pick from a list of drivers on my computer”

In the next window, scroll down to Network Adapters and double click. Then click “Let me pick from a list of device drivers on my computer”

Hit OK then scroll down to “Ralink Technology Corp” in the box on the left side. On the right side, select “802.11b/g Wireless Adapter.” from the right side.

You should get a Window saying that it

The next time you do Windows Update, there will be a an OPTIONAL update that will update the driver, and your computer will recognize it as a Linksys Wireless card correctly.

Wow! Thanks! Worked like a charm!
I just wish Linksys would make an official driver

Good job!