I would guess that the battery is Bu99erd, if you have tried to charge it already. Get it jumpstarted, check there is a charge coming from the alternator, take it for a drive (a good one of 10 miles or more) or leave it running for an hour or so. Then leave it alone for a couple of hours, then check if it starts, if it doesn't then the battery has had it, not uncommon after being left for that amount of time….