I have a SanDisk SDDR-75 USB Dual reader that I hooked up to my pc and it had worked before I hooked up my dell all in one printer. But afterwords lately when I plug in my card to the reader the drive(s) does not read the card no matter how many cards I use. All it does is blink uncontrollobly in the my computer screen I have it on a USB Extension cable and tried pugging it in with out but still came across the same problem. I think it cant find a driver. What should I do?