I was having a problem with my HTC EVO smart phone being dumb and dismounting my SD card on a weekly basis. I tried all the reformatting, replacing, erasing, cleaning, etc.. results I could find on the web and nothing worked. I finally tried connecting my phone to my laptop and running my Norton Utilities 16 Recovery Repair Drives for the SD card as a drive and it found a few weird problems. I let Norton fix them and I am happy to report that my SD card has not unmounted itself in over 2 months yea!!!!
Thanks Norton :)