key lock problem

hi, my 1995 lasabre is showing a security light, and sometimes will not start. how do i troubleshoot the problem, without spending a fourtune. thanks

take your key to a local locksmith, he should test you key for free. The rsistor could be messed up. i have the same problem that keeps reoccuring so i might have to have a security bypass. there are instructions for bypass on my last thread.