Why doesn't water burn?
You can think of water as the ash from burning hydrogen: it's already given off as much energy as possible from reacting hydrogen with oxygen.

You can, however, still burn it.  You just need an even stronger oxidizer than oxygen.  There aren't many of them, but fluorine will work, 

$$
\ce{2F2 + 2H2O -&gt; 4HF + O2}
$$

as will chlorine trifluoride:

$$
\ce{ClF3 + 2H2O -&gt; 3HF + HCl + O2}
$$