1. Which event (or what you did) before this problem started?
2. Was the NUC working before this failure occurred?
3. Do you see any video output (like Intel NUC logo for example)?
4. Open the NUC bottom cover and remove the Yellow BIOS Security Jumper.
5. Power ON you NUC. With jumper removed, your NUC should boot after 1-2 minutes into Configuration Menu.
1. Don't know, have to ask the user
2. Yes, NUC was working
3. No video output, not neither BIOS outputs nor INTEL NUC logo
4. Jumper removed
5. No, sorry, same blink code as before
Best regards HJM