1-3-4/blue isn't a documented error code, but you probably already know that...
I'd suspect a RAM issue because 3,4 = memory failure, and 1 = no memory detected. You can try this:
- Power off, unplug and press/hold power button for ~15 sec
- Open case and carefully reseat RAM modules in their slots - you may need to remove the optical drive to reach the RAM modules
- Used canned air to blow out all the dust bunnies
- Remove motherboard battery and press/hold power button for ~30 sec
- Reinstall battery (right-side-up)
- Try to boot with only mouse, monitor and keyboard connected
If that doesn't help:
- Repeat #1, above
- Remove all modules except the one in slot 1
- Repeat #4-6, above
Then swap all modules into slot 1 to see if you can identify a bum module:
- Repeat #1, above
- Swap RAM modules into slot 1
- Repeat #4-6