compression problems?

[nani]

ive been recently having problems with my 240, first i changed the battery because everytime i try to start it it seemed like the battery died. Runed fine for a about a week then the same problem came up, so i changed the alternator. everyting was great untill few days ago the same problem the car wouldnt start i had to push it to start it and last nite it did the same thing i tried to give it a jump start but it didnt work the only way to start it was pushing. so i consulted a mechanic friend of mine and he said probably it was the compression or something related. if anyone know anything please let me know