2003 Ford focus won't start

check for spark and fuel pressure , do you hear the faint sound of the fuel pump priming the system when you hit the key , are the injectors firing ?

something may have to be reprogrammed after disconnecting the batt. not sure , too much tech on cars

I have the same exact problem 05 Chevy Malibu can a auto parts store fix it

the person at the auto parts store can only guess , unless they do diagnostics it's all guess work and luck , but sometimes thats all you have , with all the tech and security systems on newer cars there's no way to tell unless you test things