Just had new PC and I didn't deactivate old nitro on old PC. Unfortunately I mistakenly started a trial when trying to install on new PC so I have cancelled that an uninstalled nitro completely on new PC. I'm a single user and don't use a great deal but it is very useful and i bought an older version and then bought an upgrade to v9. I have my original serial number but the system asks me to de-activate which I have done but on THIS new PC! I've been going around the houses since before Christma