1998 Freelander starting problems

Hi there,
can anybody help please, i used my landy all day yesterday with no signs off any problems, then this morning i went to start it as usual and it turned over but would not start,i turned it over until the battery went flat.
i have cleaned plugs and spayed with wd 40 but still nothing ........ any ideas .......

Start with the basics. Check for a spark at the plugs, pull of a plug lead and hold it with insulated pliers about 5mm from the engine block, get someone to crank the engine and see if you get a strong blue spark. Then check for fuel, remove a fuel line connection and see if fuel flows as you crank the engine

Camshaft sensor ?