2000 saturn 4dr sedan. Wont start

I have a 2000 Saturn I just bought it ran and drove
all the way from Wisconsin when I bought it I ran it
drove it few blocks daily I had an incident where it
did not want to start after I had parked and turned
it off I open the hood and check the battery cables
slam the hood and it started I had another incident
to wear while I was driving all the lights on the
dash started flashing and it seem to be losing
power I parked it started it back up and had no
problem now I cannot get it to start at all I remove
the battery and took it in for testing they said the
battery is fine and fully charged the computer
module that was underneath the battery was
setting in water from what I'm told when I try to
start it it sounds like no gas is getting to it all the
lights flash but none of the gauges will move the
dome light will not come on and the keys seems to
get stuck at times I took the keys in and the keys
are both fine what should I check for I have had too
many cars break down on me and I need a reliable
car my kids depend on me to be able to get them
to where they need to go and it seems I keep
getting screwed over every time I buy a new vehicle
somebody please help me and tell me that this is a
simple fix