From Sony's website - check out their online help and look at other 43" models since your specific model doesn't appear to be listed:
Symptom:
The STANDBY or TIMER light is flashing and the television will not turn on or produce any picture or sound.
Resolution:
Follow the steps below to troubleshoot this issue.
Verify that the AC power cord is connected securely to a working wall outlet.
Unplug the power cord of the television from the AC outlet.
Let the television remain without power for 1 minute.
Plug the power cord back into the AC outlet.
Attempt to turn on the television.
NOTES:
If the issue is still unresolved after completing all of the troubleshooting steps, service will be required.
Make a note of the STANDBY or TIMER flash pattern when referring the television to service.