98 Ford Contour

I bought a 98 Ford Contour 2.5L V 6. It had
been sitting for roughly 5 or 6 months. My
step dad replaced the following :
alternator, battery, fuel filter, oil filter and
done a oil change. My car ran good for the
first two days after doing all of this. On the
second day I filled the car up with gas but
it had about a quarter or more of gas in it
still when I filled it. I can turn it over it acts
like it wants to start but wont. I know
nothing about cars so my step dad has
been helping me. He thinks theres water in
the fuel tank since it was sitting for
6months. If so how do you get water out
of the fuel tank and fuel injectors? Or any
other thoughts what to do.