It will likely be that the reader (it's fitted in a spare 3.5" floppy drive bay?), isn't connected right?
Can you open the PC case and check to see it is correctly attached to motherboard - I think (if it is like mine), it will have taken two lots of USB connections (5 pins on each). Perhaps one set is not correctly fitted (the smart media etc card slots)? There may be downloadable fitting manual/instructions from the ASUS site mentioned, have a butchers at that, but be cautious of touching motherboard etc, without anti-static precautions.
(Basically the light will still be on if one set of USB connections is ok - it's receiving power - but the other pins passing the data through may not be. Hopefully, the leads won't all be separate but bundled and connected via the same 5/6pin connector.)
And, check also that USB is enabled - you may have more than one reference to this in Device Manager - you may also wish to check the BIOS as it can be set there also. If it shows okay, and you are confident no jumpers have been mis-set to USB disabled, then the former advice is relevant. Report back - someone will take it from there.