Another possibility - have you just filled up with petrol? If you do and then leave the car for a short while it can be vey difficult to start. The cure is to release and redo the filler cap to vent the fuel tank and then it may be OK.
Having said that mine is very slow to start at sub zero temperatures and I found 4 or 5 long (10 -15 second) bursts on the started eventually go it going.
