How to reset my security system so my car will start

Most computers are programmed to recognize a certain key. If you had a new key made, it will not work. Cheapest/fastest fix is to have the dealership with the proper computers, reprogram the computer to match your keys.

If you have the correct keys, then its possible the module that is supposed to sense the key has stopped working. There might be an emergency work around - ask the dealer. On some cars its some thing like try 3 times, then wait 10 minutes and then it will start. Don't know if or how on a Toyota.

Last option, there are tools you can get, usually from the Chinese market places that might allow you to reprogram it yourself For a 1 time job, your probably better off going to the dealer. These tools are typically not in-expensive - and you have to be careful to buy the right one (for the correct market vehicle).