Windows wont let me enable wifi adaptor

I've just installed a wireless PCI adaptor (Tenda W322P 11N) in my desktop PC but I can't 'enable' it - every time I double click it starts to enable then stops and leaves it disabled with no warning or error messages.

The system is definitely seeing it as it's listed in Device Manager, and if I bring up Network Connections (using ncpa.cpl) it's listed and shown as disabled. Why would windows stop it from being enabled??

I've tried downloading new drivers from the manufacturers site in case the drivers on the disk were old - no difference. I uninstalled it and removed the drivers and then re-booted so windows would use it's own drivers - no difference.

It seems the system has a problem with it, but surely ONE of the drivers would work if it was a driver problem?

Thanks, good thought, but I tried that driver and it made no difference.

Not sure what you mean by 'windows zero configuration tool'.

After I installed the device, when I switched on, windows automatically installed a driver.

I then tried to use the Tenda 'Wizard' assuming it would install a better driver but it wouldn't run (presumably because it could see the device was disabled) so I then just installed the driver from the supplied disk. This wouldn't work either so I went to Tenda's website downloaded the latest driver (ver 4 I think) installed it but made no difference. Then uninstalled it, and the driver, and let Windows find it and re-install it when I re-booted.

Despite all this Windows wont allow it to be enabled.

No red or yellow mark, device manager shows it operating normally: screen grab attached

UPDATE:

I read elsewhere that anti-virus progs can interfere with driver installation, so tried this:

- Disabled AVG 2011, then uninstalled the wifi card
- rebooted into 'safe' mode (with networking), installed the wifi card and let windows supply the driver
- it works!
- rebooted into 'normal' mode and it still works - BUT THE PC HAS SLOWED TO A CRAWL
- by that I mean it takes between 40-80- seconds to execute every key press or mouse click

Re-did all the above twice using the latest drivers from Tenda's website and Ralinks website - same problem with each.

So, this leaves me thinking it's nothing to do with the Tenda card or it's drivers (these are very common cards and most people on the net post good things about them) but is a Windows 7 problem (well, no suprise there.....) compounded by AVG not allowing driver installation.

I'm baffled - any thoughts?

I have been having hotspot wifi connections problems ever since I got my new smart phone with hot spot. My Windows 7 laptop would connect and disconnect. Sometimes the network could not even be discovered. I got 2 usb wifi dongles and the same thing. Connect, disconnect and no network. I was struggling with this for weeks. Nobody had answers, one close, interference. Low and behold I turned off my security camera system and bang, bang bang I had three stable hotspot connections. I was ready to return the phone because it was useless, how I'm happy except.....What to do with my security cameras?