[xubuntu] How do you scan a usb drive?

view full story

http://ubuntuforums.org – I have been using a usb drive 512mb and I unmounted it lastnight and now one folder on there has lost its contents and if I go to drag anything into the folder I get an IO read/write error. Is there a way to check the drive to see if it is faulty? And possibily recover or repair the files that are not apparently there anymore? I have got the permissions set so that reading and writing is set and allowed. Any other folder in the drive is able to be accessed and files dragged into it. (Hardware)