Hi, I thought I better sign up in case people are still having problems I was in the same boat but I just managed to work it out and have my receiver running and working on Win 8.
There isn't much to explain really,
1- grab the latest software from here and install it
http://www.microsoft.com/hardware/en-us/d/xbox-360-wireless-controller-for-windows
I used the Windows 7 x64
2- Plug Wireless receiver into USB2 port I'm not 100% sure but I don't think they work with USB3
3- go to control panel > device manager and right click on unknown device then update driver software
4- Click "Browse for driver software on your computer"
5- Click "Let me pick from a list of device drivers on my computer"
6- Then in the left column click Microsoft and it should show a list in the right column scroll all the way down to the bottom and you should see,
Xbox 360 Wireless Receiver For Windows 6.2.9200.16384 [25/7/2012]
7- Highlight that driver and ok/next and it will give you a message saying that it is not recommended or words to that extent, click ok let it install
8- Check in device manager and it should be installed and you should be able to pair your controller with the receiver as you would on Windows 7
9- Now go to the start menu and click the Microsoft Xbox 360 Accessories Status app and check the controller is paired by pressing the guide button.
And that's it I'm sorry if I made it a bit long winded but I thought I might as well cover everything in case someone needs to install one that has never installed one at all before.
I have this post on notify and plenty time on my hands so I will check back to see if anyone still cant install it but I'm pretty sure I've listed all the correct steps.