It seems the 64 bit Windows 7 driver may still be in Beta but if you don't have the one shown on this page http://www.tp-link.com/support/download.asp?a=1&m=TL-WN951Ndownload and install this one and see if that helps.
Hello, I have just bought a new pc which was built for me. The guys at the shop have told me everything is installed and working. It won't recognise the pci adapter. I have a Gigabyte MA77OT-UD3 motherboard and TP-Link draft N Wireless PCI Adapter (TL-WN951N), running windows 7 64 bit.
Any ideas on how I can get this to work?