iMac late 2011 boot problems

Hello

I have strange problem when trying to startup my iMac 21. Time from chime to apple logo appears is around 10 minutes. Also i can't get it to boot to recovery mode (no response form keyboard). Same happens with CD. If i press C button nothing happens.....

Allready done:

Change RAM

Change HDD

Changed Keyboard and Mouse

Used USB optical drive

Can someone gimme some pointers on what should i do next.