If you have an official serial number but it is being rejected, the best course of action is to contact Corel support with your proof of purchase to get the correct PIN.
If you're interested in learning more about Corel PhotoImpact X3 or similar photo editing software, I'd be happy to provide you with some general information or point you in the direction of some helpful resources. If you have an official serial number but
: During installation or upon first launch, you will be prompted to enter your activation code or serial number. If you have an official serial number but