EagleAnimus

I have an LG Optimus T (duh) that I got last August, and I have been having a major problem. I used to have a bunch of songs on my SD card, but I deleted them once I got a new ipod.
But my computer and the phone claims that I have 0 kb of space, even though i have NO pictures and NO songs, and NO apps on the SD. It won't even let me take a single picture.
Anyway, I was trying to add a custom ringtone today, and I added it to my music library (somehow. it wouldn't show up for ages) to use with an app, but then it wouldn't show up. I deleted it, and it still said 0 kb left. I deleted everything I could on the SD, but it won't budge.
Anyway, this is getting really annoying. Is there an issue with my phone that I should go to the store to fix? I have another microSD card, but it's for my camera and I can't keep it in my phone forever.

tl;dr
If anyone has any tips on how to legitly clear the entire SD card, please help. I can't add anything for some reason. Should I just go to the shop? Thanks.

AndyOpie150

Have you tried reformatting the sd card in your PC? Install in PC, then go to Start/computer/right click on the sd card/select format/choose reset to default/ the rest is easy.