2001 Chrysler Town and Country wont start

Alternator went out on my van we replaced it and
did a full tune up on it replaced the battery all
worked fine drove from MI to GA and back nothing
wrong went 10 miles away from home and turned
it off went back not 5 or 10 min and car wouldn't
start, we replaced the starter and it woukdnt start
then somehow we got it to start drove it back hone
the about 10 miles but it just died. 2 times on the
way home and now it wont start we checked the
starter we replaced the computer it started but
then the heat and air wouldnt work or raido and
windows which all worked fine before we left it run
for a while and then turned it off to try and figure
out why but when we tried to start again it only
started a handful of times and kept turning off now
nothing again we need some hel tryi g to figure this
out