98 buick century why it won't start?

[angel]

the car died, and i had it jumped, when i got home i turned it off and on did fine, next morning it would click but not start, and at times don't click but faintly can hear it trying to turn over. my lights work, radio, door dings so i don't think the battery.. we had a battery tester and it was low, so now im not sure, i tried to take it to the auto lace get it checked but now i cant get side off .if i make it come off and its stripped then im stuck buying a battery anyways. and then a starter, would like some advice on what it could be first. the battery is not dead to where it don't start. i tried to jump it again and it just clicked and nothing. any ideas. thank you