Overheating, whitesmoke from tailpipe

I hate to say it, but it definitely sounds like you have a blown head gasket. Overheating and white colored, "sweet" smelling smoke are both telltale signs of this. If it started overheating first and the white smoke came after, then you will need to have your cooling system inspected after the head gasket is replaced.

Two choice:
1. Inspect the Head Gasket; Cause: head gasket leaking coolant into cylinders
2. inspect the Engine; Cause: Cracked block leaking coolant into cylinders.

Coolant is not a flammable liquid, therefore a lot of coolant in cylinder creates starting problem. You should check your engine and the coolant system for this issue.

The first thing you can do is check the oil dipstick - you're looking for a milky brown color as opposed to a dark brown (normal) color for oil - unless you've recently had an oil change - then it will be like honey. If you don't see any discoloration - I would then look around the the bottom of the area where the valve covers are located - the valve covers sit atop the heads and if you have a "blown" head gasket - you may see evidence of water/coolant seepage. You can also take the vehicle to a mechanic, who can do a simple test using air pressure to isolate a potential gasket issue.

Good luck (remember rated this post).