I have a USB flash drive. Sandisk Cruiser. I have in it very much important stuff I should not lose them. I put the USB flash drive in my laptop. Then I get a message "disk drive not Formated. Do you want to format it now?" Of course, I clicked on "no." How can I go back to see my files? I think that has a virus on my computer. I use anti-virus "AVG FREE". also "symantec".what data ihave to post to sokve this problem.