Volvo: 1990 240 Volvo, fan belt, alternator

Question
My car dies after just going down the block. The lights and radio won't work either. When I get it home, the engine won't turn over. The battery was just replaced 6 months ago. Do I need a new battery?

My mom noticed her 1997 850 turbo the anti-freeze in resevoir was boiling?

Thanks

Answer
probably the alternator is not charging , sounds like the fan belt(s) are loose ,the water pump shares the belts with the alternator. some 240s have 2 ; in your moms car: maybe her pressure cap (prevents boiling) isn't working or isn't tight , that will allow the coolant to boil? i have never heard of this though, is the car overheating?