Have you looked at the responses that people posted in your other thread on this topic a couple of days ago? >>>>Unable to start my Nissan Altima
Below is what I posted at that time, and there may be other posts in that thread that are relevant, as well:
A blown head gasket CAN be the death knell for any car. The Altima is not unique in that respect.
The ultimate question, therefore, is…How long ago did the head gasket become breached?
If it was breached a while ago and you have been driving it in that condition, then it is indeed possible that the engine’s lubricating oil was diluted with coolant, and as a result bearings, piston rings, and cylinder walls in the engine were damaged. Or, if the breach was of very recent origin, it is possible that the engine has survived major damage.
However, if the engine turns over but doesn’t start, I have to suspect that there is inadequate compression in the engine as a result of major internal damage, and if that turns out to be the case then you have to decide whether to get a replacement engine from a junkyard, or to ditch the car.