i have 1998 ml 320 i have problem with cranking long befor it start's
next problem we had a big snow storm here on the east cost i drove to in the storm after i get to work i trun off the car and all the dash light where on try to start the car no start after about 2 hour when back dashlight was on still but the car start ok turn it off wont start . pls any help is ok i dont what the problem is

 

extended crank is usually the fuel filter/ fuel regulator. the regulator holds the fuel at the fuel rail for start up; when the regulator goes bad it wont hold the fuel pressure there. and causes extended crank. check the fuel pressure at the fuel rail should be about 60psi and stay there until you start up again. not sure of your other issue,

 

Chassis221 is right, replacing fuel filter should fix your first problem (long cranking before starting). Fuel pressure is can drop down to minimum of 36 psi after 30 minutes.
Your second problem is bad battery or bad connection on battery terminals.