My Peugeot 605 Won't Start - Please Help!

I've recently had some issues with my Peugeot 605 and I'm hoping someone can help me out. The car won't start despite trying to jump-start it several times. I've checked the basics such as the battery connections, air filter and spark plugs, but still no luck. The fuel gauge is also showing empty which seems unusual since I recently filled up. Any ideas would be greatly appreciated!