1995 Honda Accord Batter

Hi, my girlfriend recently had the car and the battery died she told me that someone tried to boost the battery but had the connections backwards. When they finally realized they had it backwards they tried connecting the correct way but to no avail. We had the car towed to home and I replaced a fuse under the hood that was blown in doing so it made the car start but wouldnt keep a charge so we bought a new battery. When we hooked up the battery the car started but when I removed the cables the car just shut off. We then had a alternator installed which worked for about a day and died while in the process of driving. Could any of the fuses under the driver side cause this or is it a full electrical problem that needs a mechanic? Ceyron