How to end the game?

Some background before some noob questions:

My first 'real' (or so I thought) game, customized race, picked 4-5 different victory conditions. Finally conquered all major race colonies/planets, one of victory conditions fullfilled, no end. Hmm, there are two minor races left, lets get rid of those colonies also. No end. Hmmm, what is left, yes, there are two fighter groups of one major race and two drone groups of one minor race. Let's get rid of those and may be the game ends. Well, you can quess. I have slow dreadnoughts so I cant beat fighter groups. Hmmm, lets chase those untill their all of supplies are used. And, when finally those are without supplies, they start to circle on battlle screen! No change to beat them, not in tactical or strategy screen. No end of the game...

And now those noob-questions:
1) is there end of the game?
2) if I select several victory conditions, should I fullfill ALL of those, not only one of selected?
3) isn't beating major races enough, should I beat minor races also?
4) should I beat also all enemy ships/bases/unit groups before final victory?
5) how I can beat those unit groups or is it possible at all with my current ships?
6) if I do quickstart (standard SE5 game), what are base definitions like
a. victory conditions
b. enemy quantity (how many AI races)
c. size of galacty
d. difficulty level

So many questions...

Wenla