Ok could be a blocked carb, all the crap when you ran out of fuel blocked your jets. Take carb apart. Sure filter isnt blocked?
Sometimes you may get lucky if you do this. remove spark plug and pop a little fuel, teaspoon full, down bore and start as normal. This may well kick things into life. If it goes for a bit and then stops try again. If it keeps doing this then your carb is almost certainly blocked up.
bb, April 2010