I/O Error

I have an EMachines W3507 desktop PC and am having issues with a Sandisk 4GB microSDHC card with adapter. Every time I plug the card and adapter into the reader, and go to my computer, I keep getting a message about an I/O error. I have tried 2 memory cards of the same kind. The cards themselves are still readable by the phone they go into, but the computer just won't read them. I'm sort of computer literate, but I get extremely confused when alot is thrown at me at one time. Please try to keep it as simple as possible.

I am thinking that your drive letters for your flash drives are in used or reserved to other drives.
This happened to me with completely functioning flash drive. but not working on my PC because its drive letter that the flash drive is supposed to used is assigned to other drive then its not showing on my drive list but showing on disk manager. if this is the case then you have to change its letter, here is how: http://www.online-tech-tips.com/computer-t…-or-hard-drive/