Anyone Help

Hi there fellow 4-runners. I need some help for my newly purchased 2000 4runner. Just bought it about 3 weeks ago. Runs great, Then i bought a home depot chip key just in case (80.00) and it worked great then a few days later. it didnt start for a few minutes. I thought it was the back door not closed properly closed it and it started. then 2 days later no more start with neither OEM master key nor the home depot key. The security light wont stop blinking even when inserting any key. I purchased a junkyard immobilizer ring and computer (ECU or ECM?) had the memory cleared and still security light wont stop blinking, so truck still wont start. Help, scared to go into a rabbit hole just buying different parts. The trucks electrical all works, it turns over well, but no spark. I've been reading that the light needs to stop blinking when key is inserted and recognized.Dont know it he home depot key had anything to do with this? but I'm still at a loss. Any help, suggestions from past experience will be greatly super duper appreciated.Thank for reading this.