Well i'd say there can only be a couple of causes. Either the reader port is broken, or you've not got the right device drivers installed. I had a problem with the webcam on my AR51E but the device manager showed no problems (was installing the default windows driver). I'd find the entry in device manager, do 'update driver' and force the choice of the driver from a list, to make sure windows isn't installing it's own crappy driver
Other than that, if your laptop is 'wipeable' you could always do a complete restore and see if that fixes the issue. If it doesn't then you can be guarenteed it's a hardware problem.
Sorry I cant be of more help.
