I put on a new alternator on my 2000 Chevy Blazer and it still wont start
Recheck all wires,for good connections,and if that fell,s to be,check your fuse,s.
Check battery voltage. Without a good fully charged battery it will not start. Inspect, clean and tighten all battery connections. Also inspect the negative connections on the frame and motor. FYI Your alternator charges your battery only when vehicle is actually running. It does nothing to help start it.