Problem with card reader Acer Aspire 4520

I have an Acer Aspire 4520 laptop. It originally came with Vista Home Premium 32 but I upgraded some time ago to Win7 Ultimate x64. Everything has been working fine but I never had used the built in card reader before. Recently, I inserted a memory stick (MS) duo adapter and although the card reader recognizes the memory stick (in My Computer), when I click on the icon in My Computer or right click to format, I always get "please insert a disc into memory stick" or "there is no disc in drive H, insert a disc and try again."

I have tried EVERYTHING I can think of or have read about and NOTHING works. I have downloaded and installed the latest memory card driver from the Acer website. Thinking that the adapter may be faulty, I bought another MS adapter with the same results. The memory card itself is fine as it works in the camera and I can hook up the camera to the laptop and download pix fine. I have gone to Disc Management and changed the drive letter for the MS. It shows up in Disc Management in sort of a vague way but says "no media". In Device Management, there are no yellow warnings and it says that all drivers are up to date and everything is working properly. I left the MS in the card reader and then rebooted the computer hoping it would be automatically recognized. I even scanned the memory stick for viruses and it's clean.

So what do I do now?! I am out of ideas. It seems like a driver or software issue. I would greatly appreciate any help. Thank you very much.