Dont just chuck the card in the bin or buy a new one as this fix is 100% guaranteed to work.
Go in to device manager and right click on your card and select properties.
Click on the last tab called Power Management.
And untick the box that says "Allow the computer to turn off this device to save power"
Click on OK and then try to conenct to your wireless network again, this works with all versions of the driver from 2008 upwards and with WPA2 / AES encryption.
If you are still having issues then i would go ahead and see if there is a newer driver and make sure that the same settings are applied as above.