Nitro PDF uses you boot sector to store its license information. My Nitro PDF with OCR was not showing the OCR as being active so I decided to uninstall and reinstall. I deactivated first then used Revo to uninstall. The uninstall hung up and the system completely locked up. A hard boot brought up Windows 7's boot fixer utility which played for a few minutes and then the system restarted. I couldn't find Nitro PDF nor would Revo show it so I tried to reinstall the software. The reinstall went fine but the software would not run giving this error. “Multiple Restore Hard drive operations damaged the license and the product must be re-registered. #2” As I'd had problems with their license when using a cloned drive for backup and also when I restored my system from a backup I decided to give the software the flick. I complained to the support people and asked for a utility to get their stuff out of my boot sector but they just play dumb. They said use Revo (I had) and provided a clean-up utility that doesn't do the job. No software, other than a hard disk utility, should be allowed to play around in the boot sector.