Why will my car start but won't continue running ????????

So I just bought a 1996 Honda Accord off
craigslist . It has about 256k miles on it. Car
hasn't given be any issues and I've been
driving it for about a week. I just recently had
my radio installed. The guy couldn't get any
power to the radio so he used the ground
wire to get power and it begin to work. I had
no problems starting the car and I was able
to drive it all that day. And I drove it to work
the next day listening to music as if all was
fine. When i would turn my car off and even
take the key out however the radio would
still be on, I had to literally hold the power
button to have it turn off. That day when I
got off work around two I picked up a friend
and he looked at my car for me before we
went too far in it. He put coolant in it, water
in it and we began to drive on the freeway.
My check engine light went off but came
back on eventually. Then when we were on
the freeway the car gave out. We were still
moving and even able to exit the freeway
and pull over to park but when he would
push on the gas it wouldn't give.  we
couldn't figure out why it gave out . He then
noticed how my radio was set up and he
said maybe the ground wire blew everything
out. He said it could of blew up, and that it
blew up fuses . We got a jump from
someone and the car started we were able
to drive and I parked where we could grab
something to eat. Just to be sure after sitting
parked for a while I started it up again to
make sure it would start and it did. But then I
tried again when we were actually ready to
leave and it wouldn't fully start. It wanted to
kick over but it wouldn't. Even after receiving
another jump it served no justice. He then
looked further into the car and said oil was
leaking somewhere. He changed the gasket
and cleaned out the oil he changed the work
plugs and everything . Car still won't start.
He thinks the ignition switch is blown, and
the fuses are shot. What could it be? And
did it have anything to do with coolant being
added cause I was driving with my car fine
until he put that in. And was it wrong to have
used the ground wire to install the radio with
no amp? Please help.