I have a 95 Olds Cutlass with a 3

I have a 95 Olds Cutlass with a 3.1. My problem is it won't try to start. Came home one morning from work and was going out later that night. The car acted like the battery was dead when I tried to crank it, the radio and lights came on but no starter click or rotation. Noticed that the security light was blinking in the dash as well. I have cleaned the positive and ground wires at the battery and starter, had starter tested and it checked good, had battery put on a charger for several hrs. Was told at local parts store that the anti thief relay may be the problem. Could this be my problem or do I need to look else where? And if it is the Anti thief relay, where is it located? Thanks for any insight to this issue