replaced starter on my 2003 mitsubishi galant now not starting no spark also check engine light lighting up can i get some help with this plz

 

First, all you did was replace the starter, you disconnected the battery when you changed the starter and that was all that you did correct?
If that was all you did and did not disturb any other connections, it is just a coincidence that your car won't start now.
Let's assume that it is a coincidence, and you do not have any spark.There usually is a crank or cam position sensor that controls when to fire the spark plugs.
Also as you have a CEL. If you can get your hands on a scanner that can indicate the code #, then you can search the web to find out what component to look at.
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