bmw 735i 1988 wont start

hi i have a 1988 bmw 735i that wont start i have a start switch n it but when i push it after turning the key nothing happens im wondering if it might b the anti theft on the radio all the warnign lights turn on but nothing else works but it use to liek 5 days ago pplease get back to me

Sounds like you just have a dead or very weak battery.