Sorry i am new at this and know little to nothing about computers. I have a gateway 400vtx; recently the fan stopped working;I get this message as soon as i turn it on
ERROR 02FA: fab error!! please turn off system and check your fan!!!
i want to know how long i can keep using my lap top until it starts to damage internal parts? so far i have been using it, the system still works fine, in 20 min interval and letting it cool then start again, is this causing just as much damage as letting it heat up? I really need to use my laptop and can not get it serviced right away, how big of a chance am i taking of damaging more costly parts?

You are definitely taking a risk. Heat is more of a problem in laptops than in desktops even, because of the confined space. You are definitely tempting fate to continue using it when you know the fan is not working. You could try blowing an exterior fan in through the exhaust opening to get a little airflow, but I strongly recommend getting it repaired right away. You say you don't have time, but if it fries, you'll have lots of time, and you won't be happy about it.