No work showing in my USB

Hello!,
For some unknown reason no work in my Sandisk Cruzer USB shows up, I'm wondering if it has something to do with windows 7. Every time I put the USB inside the port, the folder of it then comes up and there's apparently nothing in there. However it works perfectly fine on the computer (I have my own laptop), but the computer has Windows XP instead of windows 7. And i really need the USB so I can put in my school work for my upcoming GCSE course works.
Please help me and thank you.