ok since you have the dos boot disc your in good shape, first pop in the boot disc and follow the instructions on the DOS boot disc. then once you get into dos and get at the command prompt then type in the following codes, after you plug in the USB Drive.
1.xcopy C:\(were ever the files were located) E:\
2.(you may see a confirmation asking about this and if you see this then type y)
3.(after it finishes copying, wait a min or two and then unplug the Flash Drive)
this should work, but if you have any probs then plz dont hesistate to reply back.