RISHITECH

I have been seeing this problem for the last few days.Whatever files and folders and store in my USB drive,next time when I access are seen as hidden.Also when I try to uncheck the hidden checkbox from the properties,I see it disabled.I use a moserbaer 2GB USB drive.Also I am using USB disk security software v.5.0.0.80 for protecting my PC.But this thing is happening even when I don't run USB disk security software. Anyone have faced the same problem? PS:I am using Norton Internet Security 09.