i have my profile on a flash drive but on my PC it says there is nothing there
Short answer... you don't.
The xbox formatted the flash drive in a way that the PC can't read it. When you first put the flash drive into the xbox you were asked to set up the drive. At this point the xbox formatted and encrypted the flash drive. When you put it into a PC and get the message that the drive is blank, do you want to format, the drive is not blank, it just can't read it.