How do I access folders changed to unix files?

I am using OSx 10.7.5; today I put my USB stick into a computer in a shop to print out something, and now all my files have changed to Unix and won't open. It looks as though they are still there, as it is showing as having 3.4 gb full on the stick.

I have looked at various postings, and there seems to be a suggestion that this is to do with Launch Services (although I don't understand why the folders on theMac itself are normal), but I can't see any instructions on what to do for this version of OSX.

I backed up the stuff a few days ago, but therefore have 3 days work which will; be lost if I can't open the files.....

Help! Please!

Many thanks

Nizam