Start up looping

[Equis77]

My 27" imac 2013 OsX El Capitan - 8mb memory - spinning harddisk. keeps on starting up after the first chime. (looping chimes) I have already tried reset Pram/Vram - Reset SMC - Startup Manager - Safe Mode Recovery OS (+internet recovery) and single user mode: What can be the problem?

 

[rpmurray]

All the magic smoke has escaped.

Joking aside, have you tried booting from an external drive? This could be the hard drive failing.

 

[Equis77]

Yes I have tried that