I've been away from web building for a long time (5.0) and needed to get back. I wasn't finding a limit to how far back the 2015 Upgrade was allowed, so bought the upgrade. The system is telling me it doesn't recognized the 5.0 version serial #. I have the the serial # written on the original CD of 5.0, so entered that when prompted. Any suggestions, I've obviously had several computers since 2.0, so it was never loaded on the current computer? Thanks!