this also happened to me, but it was the little pins that were to blame. one was recessed and then broke off. card couldn't be read. got another optimus from a friend and it was a rebooting one. I took a look at the slot and bent the broken pin up to make a connection.
not saying thats your case, but I would do what above said and connect it to your computer and see if it shows up. windows may notice the error and prompt to repair, if not, do a chkdsk.