can a king be use to fight and win the game

The king is often an important fighting unit in the endgame... but as Alex says, you cannot checkmate with the king alone.
The king is often an important fighting unit in the endgame... but as Alex says, you cannot checkmate with the king alone.
Very true. That's why the kings leave the safety of their castled positions/back rank in the endgame.

The king can be a very important offensive piece in the endgame and very occasionally in the middle game too (see Short-Tinman, its worth checking out this game).

The King is a very important fighting unit in endgames, but sometimes a middlegame situation calls for the King's abilities...
http://www.chessgames.com/perl/chessgame?gid=1124533
Probably the most famous King March in history... NIgel Short ties Timman up in all over the board, and then uses his monarch to march through the pieces and help the queen deliver mate. Timman can do little but watch as Short's king comes to deliver execution himself. A thing of beauty.
EDIT: Thundercracker... great minds think alike.
I was playing chess on my computer when came up with a idea wich is atheory what if you can use the king to fight with and wine with? thank about it and try it leat me know what happen?