"chess problem" software (free/paid) to download for PC? I tried one a while back but it was quite elementary, it had a few thousand problems but did not give detailed answers, just one single move as correct and that's it!

I do play Chesstempo sometimes but don't always have internet connection and also I want something I can have on my computer if I'm outside or somewhere there is no connection so I can do that, one with range of problems, not just tactics but like endgame stuff too that sometimes is more tough to calculate than tactic. Any programs you're aware of? 

Edit: I only saw a thread on training particular chess tactics but that's not what I'm looking for, just chess problems of all sorts.
LucasChess is the best free software out there. You can add any engine you like and you can analyze your games with multiple engines. It also has a training mode for tactics, openings, and endgame.

I highly recommend it. I recommended it to a friend who loved it so much that he hardly uses his Chessmaster these days.

Here's the link:

https://www-lucaschess.rhcloud.com/