Can I buy a control board at Lowe's or Home Depot or do I have to order?

I'm guessing you need a control board for a furnace, is this correct...

It would be helpful if you would give BRAND NAME and MODEL #

Did a search for control board at Home Depot -- Gate Opener Board

Did a search for control board at Lowe's -- Glue Traps for Mice

furnace control, Heating, Cooling Air, Industrial Supply, MRO items on eBay.com

Yes a furnace... the air conditioner works fine... but the heater blows cold air and its in the attic... and the air conditioner is in the yard... what exactly is in the attic a heater pump??

Before you start replacing parts you should have it diagnosted by a qualified service person. These parts can get very pricey. Good luck, Mike

So we know your furnace doesn't heat -- is it gas or electric

Heat source is your problem -- more info please