The "upgrade" prompt was likely an invitation to purchase/license VP.
Some time ago there was an option under UNinstall in Windows Programs and Features to keep using the free VP version after the trial expired - with limitations on export formats.
It seems that option is no longer available.
To fade in an overlay clip that has no overlay clip preceding it, click the fade symbol at the top-left of the clip on the timeline, then set the duration.
To dissolve adjacent overlay clips, use a transition. Crossfade, for example.