Mac booting loop, I can't recovery or boot from USB im having a big issue with my iMac mid 2011, last night the Imac just reboot itself and after that i can't use it. 

There is a white screen (see picture), the logo and loading is always there, sometimes the loading dont get to the end and the Imac reboot itself, an eterna loop of reboot.

I tried all methods about how recovery with USB, from Internet, from the recovery partion and nothing works, in fact the OS doesn't load any visual window like OS X Utility.

The thing is that i don't know if this is a hardware problem like HD or if this is a software problem.

I have the MacOS Sierra

Any idea about it?

Thanks
You might want to try to boot into Verbose Mode. This is a regular boot process, however, the graphical screen is turned off in favour of a terminal-like screen logging everything that happens during boot. This may give you the chance to see an error message indicating the cause of your problem. It is not too likely yet still possible so do give it a try.

To boot verbose you need to press cmd-V upon startup. You may release the keys just after the boot chime has passed. The screen should immediately switch to a white font on a black background. You need a fast eye to read these (cryptic!) messages as you cannot hold them. 

Good luck!