MacBook Pro :: Won't Read SD Card But Will Read CF Card With The Same Card Reader?

As the title says, I have a card reader that works great with a CF card, but the MBP won't recognize an SD card. This is a new problem for me. I also have an express card adapter for SD that won't read the card, either. I have tried 4 different SD cards, and these exact cards have worked for me in the recent past (within the past 2 months). They work fine in the camera. I also tried connecting the camera via usb, which was unsuccessful. I tried blowing air on the cards and the reader. I cannot get the cards to be read on my wife's macbook. This makes no sense to me, as it worked fine the last time I tried. I find it hard to believe that all cards are corrupt, or the cable is the problem because it reads the CF card.