|you could try the following.|
look for a switch on the side of the usb drive(just in case you clicked it accidentally)
open a command prompt and type
xcopy f:\*.* c:\usb1\
see if it copies all your files to that directoryc:\usb1, and if they are openable.
(f stands for whatever the drive letter of the usb is so if its g it would be g:\)
if it doesnt let me know