Hi, I have 2 SanDisk USB sticks which for some reason cannot be made bootable anymore. Not even with the official MS Windows 7 USB/DVD Download tool. Reformatting the drive doesn't seem to help. But I know that some time ago I was able to use them for this purpose. I have since used them for printing jobs on public PCs at a local copy shop. I have also used them on other OS such as Linux. What could have gone bad with these drives in the mean time? Is there a way to troubleshoot the drive and bring it back to normal?