Can anyone help me figure out why my car dont turn over

Hello everyone I'm new to this and im having problems
trying to figure out what is wrong it's a 2005 Nissan xterra
manual so about 2 weeks ago everything was running fine
and it had no issues  then one day it just didn't want to start
so I charged the battery (it is 3 mouth's old) and it turned
over but made a funny sound and turned off and now it
wont do anything.
I started with the starter and it was bad so I changed it out
check the alternator it was still good I changed out the
safety switch changed out the fuses made sure all the
wiring was connected and grounded and all that and when I
turn the key the lights and everything still turns on but it
wont turn over or start the other day it turned over just for a
day but didn't want to start if anyone has this problem
please help me I have no idea at this point.