[Kriskouki]

Most of the time that the car won't start, I would look at battery, fuel and spark.....But, it seems that you have done all.....

Now you may want to look into your mechanical work you have done......If the car start before the head gasket failure, it should be started now......I am sure no electrical components would failed by the time you have done your head gasket thing.......

Check your timing as if you are out of timing, it won't start anyways......

Lastly, do the compression test.....It will tell you many of things.....One important thing is will will tell how you that the valves are leaking or not, which will also lead to your camshaft/timing setup on your system......