Does it go immediately to red flashing or do u get a brief glimpse of yellow 1st?
If you see any yellow then your GPU/CPU will need a proper reflow.
If it goes immediately to flashing red, most likely your power supply has gone bad.
Thes are both relatively straightforward repairs but whatever you do, DON'T EXTRACT YOUR DISK until you get the console repaired.
You will save youself a lot of grief if you take my advice. I can't count how many Bluray drives that I have had to disassemble and reset because of the instant urge to get your game out of a broken console. Don't panic and just leave it in there. You will get it back when the console is functioning again...
Hope this helps!