Can't read files on Flash Drive

I have a officemax flash drive. I have no problems with it until today. I was trying to copy photos to it so i could clear up some space on my hard drive. it said "preparing to copy". and then, there was suddenly no space left on my flash drive but i could not see a single file. I went from 256mb of space to 0 space but, as i said, cannot visualize a single thing. Any suggestions?

Try emptying the Trash and see if that clears up the space.

BLESS YOU! That was brilliantly easy. Thank you.