Okay...I left the installation of Paint.net running overnight. 10 hours later the progress window is still open and "progressing" and contains the message: "Optimizing Paint.net's performance for your stystem. This may take a minute."
If you need it, my system specs are: Windows 10 Home, Intel Pentium CPU G2030 @ 3.00 GHz, 4GB RAM, 64-bit Operating system.
Any clue as to why Paint.net will not download anymore?