My car wont start

I have a 1996 Olds 98 Regency we put a new alternator in it about 3 days ago ran fine the past couple of days then took my car to get oil change done the Tech went to start the car and it wouldnt start wouldnt even click over there is a new battery in the car the starter is good the Techs think it is something to do with the security I have to keys same type and all when I put the one key in the security light flashes and with the other one it doesnt I have been trying to look up things that might be wrong with my car on the Internet if someone can help please and thank you

If the security lite stays on or flashes the car will not start, unless you try the relearn procedure which can be found with a site search Vats relearn, after that you may need a pro to get involved.