Problems with MAC, help pls !!

Hi,
my friend has serious problem with his MAC. After turning on, operating system won't start and screen remain white - grey with blinking question mark or prohibiting symbol. This is going on for two weeks. He was using MAC support but without any results.

Does anybody have any idea where is the problem?

Thank you in advance for help.

J.

 

Have he tried to boot from the recovery HD?
Restart the computer and after the chime press and hold down the COMMAND and R keys until the Utilities menu screen appears. Or restart the computer then after the chime press and hold down the OPTION key until the boot manager screen appears. And then select the Recovery HD and click on the downward pointing arrow button.

 

Will ask and let you know asap.

Thank you for now.

 

Hi,
it took a while to hear my friend ... he did already what you've suggested. But it didn't solve the problem.

Any ideas anybody ??

Thank you in advance.

 

I think his problem can be resolve by this guide provided by apple support.

 

He is following apple support but with no result.