Hi,
I ran into exact the same problem.
What I did
Install latest paint.net from web
1. Downloaded and extracted paint.net.4.2.10.install.zip
2. Run the paint.net.4.2.10.install.exe.
3. It finished the paint.net extraction installation part to the point where a window pops up so shortly so you can't see and read it.
4. No installation assistant starts and nothing happens.
Install trial paint.net from windows store
1. Did install the trial from the Windows store. This worked, but...
2. Start paint.net. Abbortion with error message: Net Framwork 4.0 missing (my Win10 is already on 4.8)
3. Uninstall paint.net
Skype
Skype tells me: skypebridge.exe .net framework initialization error.
I believe there is something messed up with my framenetwork setup.
So I went on to repair my framework.
Repair Window 10 files
1. Followed these instruction https://support.microsoft.com/en-us/help/4026529/windows-10-using-system-file-checker
New try: Install latest paint.net from web
1. Finally installation works.
2. Happy? No! When I start paint.net: error message (null)
What else did not work?
Install latest Framenetwork 4.8: Already installed.
Reinstall Framenetwork 4.8 and install Framenetwork 3.5.
Repair Framenetwork: netfxrepairtool.exe
