So today I had to buy a new battery for my 1999 two door Tahoe. I went to the closest store because my battery was on its last leg (advanced auto parts). They tested it and the computer said the battery was bad. Well after purchasing a new battery, the employee offered to install it as they always do. As I left the tahoe sounded like the starter was bad and had some weird noises. I stopped at another advanced auto parts and wanted them to check my alternator and starter because of this and with further inspection I noticed the negative cable wasn't even connected, only the winch cable (negative) was connected to the battery. So my question for readers is what can go wrong electronically for this kind of mistake by an employee at advanced auto? The only ground it had was from my winch that is attached to a brush guard that is bolted and welded to the frame, it obviously wasn't a good ground due to the rough start and noises. I plan on emailing advanced auto parts to see what they have to say. Any suggestions on what I should say/explain to them about the possible damage done to my electronics due to their mistake. I was honestly surprised it even started and drove in that condition.