Have you done any work on it recently, or had any done? If the REP light is on, the CEL should be
on as well. Check for codes? REP can come on for any number of reasons, as anything that could
damage the engine or drivetrain and can be read by a sensor can cause the PCM to turn it on and
go to limp mode. Throttle position sensors, accelerator pedal sensors, damaged fan wiring interrupting
the 5V reference, excessive misfires, variable timing problem.
The no start condition could be a bad ignition switch, battery problem, starter relay, or even a bad ground. When you say it won't start,
is it at least cranking? If it's cranking, do you hear the fuel pump do a 2 second priming before you turn the key
to the start position? If you don't, fuel pump may have died, or the relay might be bad or have a bad connection.
So, if you can work up some more details, maybe the forum diagnostics machine can figure something out.