Installed a new heater blower and now car won't stay running. Someone care to give some intelligent insight?

I replaced the heater blower motor. The new blower works fine, but now my car starts and runs for a second and shuts off! The security light on the instrument panel stays illuminated now. Someone told me this is the PLOCK security causing this. How could this be so when the car was running perfect before I installed the heater blower? I am stumped and don't know what to do. When I try to start the car it just won't stay running! The interior lights and the fog lights also don't work now. When I try to start the car it acts as if the fuel is being cut off from the engine. It will NOT stay running. I hope there is a good mechanic out there somewhere that can help me out with this problem. I heard a new plock (ignition switch) will cost 500 dollars. I don't have that kind of money right now. Times are tough these days. Please, someone give me an intelligent answer, I want to desperately trade this nice looking piece of junk off and get a Ford. lol