When I insert any working microSD card into the drive on my LG Optimus V phone, I get an error message that I have a damaged SD card and need to reformat. I reformat the card and get the same message. How can I solve this?
SD cards of any type are notoriously easy to damage with static electricity. Usually when they are damaged, your can't repair them. If you have files on the disk that must be recovered, a company like Kroll Ontrack might have some success but will charge you hundreds of dollars.
If you just need a functioning microSD, my advice is to buy a new one...
Try doing a factory data reset or a firmware update. I haven't used LG but, in sony there is an update service where you can repair the firmware. if LG has an option like that, try it! if the error still comes, take it to a service center since I don't advice you to do hardware repair.
Check to see if the card works well on a PC. If it does, there's a problem with the phone. Check the contacts, or do a hard reset as HA14 suggests.
use kill disk attach your sd card to card reader and format it using Killdisk download from here http://how-to-erase-hard-drive.com/
see if you can update the firmware, if not do hard reset (first do backup of files), you can also use Astro file manager to do backup of installed applications.