Tried setting the Compatibility mode to Win XP SP3 for the VST.

That didn't help.

Thought about changing Plant Tycoon to the same compatibility mode but am leery about "fixing what's not broken".

Looked into the .NET Framework 2.0 and on the Win7 it is incorporated into the Operating System rather than having a stack of versions in the Program Files like on the XP.

Maybe VST can't "find" it?

I may try to load them both (PT & VST) onto the Win10 just for fun.

Time to delete more seeds!