okay, i cant get any heat from my vents. the blower is running, i can hear that, i replaced the tstat, topped off the anti-freez but still no heat. Now im freez'n! any suggestions please!!! Thanks

P.S. I did some more research and found some suggestions from puchasing a new heater core to flush or back-flushing my existing heater core. Since replacing the core costs $$$ and, from what ive been told a pain in the you-know-what I'd rather stear from that. How do I flush/back-flush my core? heck is this even the right direction?