I have a Nordyne furnace the thermostat will not allow my fan to turn on when it heats up.. I have to manually turn the fan on... Could I have done something to the thermostat? I too can not afford a techie to help... Please any advice?

I have to manually turn the fan on...
When you say this are you spinning the blade to give it a boost to start? Or are you setting the tstat to fan instead of auto ? To get it to run
If it's the 1st ,spinning with your hand you may need to replace the capicitor which is very cheap with an exact match of the old one