No heat can be caused by?

Sorry, reading the other thread about the fan not blowing hot air and one of the responses I have a question (again) please

What are the causes of there being no hot air?

If the head gasket packs in , does this cause this problem?

Again sorry for appearing a *bit* dumb...

well a blown head gasket can cause this
a leaking heater matrix,its like a radiator inside the car than gives hot air
a worn water pump not pumping coolant to the heater matrix
an airlock in the coolant system
a stuck open thermostat stopping the car heating up fully

hmmm alrighty then

Just after my friend going by what I told him on the phone reckons the cause of all my woes was the head gasket going, he said the car shouldn't have been driven etc etc

and one of the effects was the heating stopped working, as I remember it just being another hellish thing to add to the horrendous driving

sorry to ask all this silly questions

I will go do something girly now

well the head gasket going would kill the engine if it was used after it had gone.
basically you have a top and a bottom to an engine.
these are bolted together and sealed via the head gasket(head is the top of the engine)
there are channels running through both halves for coolant and oil.
if the gasket goes you get poor running,over heating to name a couple of symptoms.
if oyu keep going the head can/will warp often to beyond repair and then more engine damage can occur.