Winboard is excellent - paste in the pgn - edit the games - copy
the fen etc - also much better than that 'analysis tool' for choosing
quick moves whilst at work.
I can copy a pgn from here and post a position from the game within
seconds as I did on here a few threads ago.
The diagram I can vouch for - the analysis..... 😕
Yeah, Winboard and Arena are good choices. Even simpler is Chesspad, although it's limited to only Winboard engines.
http://www.wmlsoftware.com/chesspad.html
Another suggestion is Scid, although Scid has so many features that you might think it's getting too far away from the "simple" concept.
Links for Scid:
http://prolinux.free.fr/scid/
http://scid.sourceforge.net/
http://scid.sourceforge.net/download.html
As a side note, I was recently finishing up my study of Pandolfini's Endgame Course book. I found a PGN file of the book on the internet, so I pulled up the PGN file in Scid so I wouldn't have to waste time setting up the positions on a board. Well, I had recently reinstalled my 5-piece Nalimov endgame tablebase onto my PC - And I was scanning the Scid options and found out if you give Scid the path to the Nalimov files, it will automatically spit out tablebase info any time it sees a position covered by the tablebase files. How cool is that? (Keep in mind that you don't have to have an analysis engine running - Scid gives you this tablebase info directly through the GUI.)
I found that this tablebase capability was useful for "what if" moves. And since over 90 percent of the positions in the book were 5 pieces or less, it really came in handy for this book.