Start the computer and only show a folder with question mark

For some reason your iMac cannot find a bootable volume. Reinstall Lion by holding ⌘ R at startup.

What I should do ? Is there any 3rd party tools that I can try do use to solve this issue ?

I would avoid using any. If Disk Utility reports "no problems found" then that's as good as it's going to get. If Disk Utility finds problems it cannot repair, the disk is already damaged and should be replaced.

You probably don't need any third party tools. Apple explains exactly how to troubleshoot this issue in this advice letter:

http://support.apple.com/kb/TS1440

If your machine is a newer mode what has probably occured is your system has "forgotten" where the startup volume is. After you have started it navigate to System Preferences - Startup Disk and make sure the internal HD is highlighted, then click Restart to test.

leonel junior wrote:

I boot from the Lion DVD,

There are no Apple supplied Lion boot DVD's , you use command r to boot into Recovery HD partition, if that doesn't work good chance the drive is dead, it likely will have to pulled to test any data recovery efforts made.

I turned off the computer and next morning I turned on agian and this time with no problems, I use it for a few days with no problems but yesterday it happens again...😕

Hold Shift key upon boot to fix the drive, reboot holding option and select OS X to boot and head to System Prefs, change the startup drive to OS X.

If you can't do this, your looking at data recovery efforts or repalcing the drive, total erase & restore.

PS: when the iMac started up with no problems I run disk utility and made a repair disk to the mac HD...

The option key, set startup disk in system prefs should resove the issue.

https://discussions.apple.com/community/notebooks/macbook_pro?view=documents

leonel junior wrote:

Hi rkaufmann87,

What do you mean with "newer mode" ?

Thanks!

Sorry I meant newer model. If your machine came with Lion already installed the chances are slimmer that the HD has failed. However if it's an older model I was thinking the HD could be failing. If you can boot to the Restore Volume of Lion this is a good sign the HD is OK. Next time you try to boot, hold down the Option key and if the internal HD shows up choose it and let it boot. Then navigate to the System Preferences - Startup Disk as explained in my first post.

leonel junior wrote:

That's true but a burn a bootable DVD after the Lion release...

Yes, just checking, we get all skill levels in here. 😉

leonel junior wrote:

Hi,

I'm already at home, and tried to boot holding the option key, but only the mouse arrow shows and nothing to click on...

What can I do more ?

Thanks!

Just to double check, you held down the Option key after you heard to Startup tone. If so then the next stop is to run Apple Hardware Test in Extended Mode. This will test the hardware and I believe it will report an error code. Unfortunately Apple doesn't not supply the translations to those codes but someone on the forum may have an idea, however whatever it is my suggestion is to take it into your local Apple Store or AASP for service.

http://support.apple.com/kb/HT1509

leonel junior wrote:

I'm already at home, and tried to boot holding the option key, but only the mouse arrow shows and nothing to click on...

Nothing shows, the firmware has nothing to boot from.

IT may mean the drive is mechanically dead, or the partiton map on the drive is bonked or it can't find a OS X to boot from.

Hopefully you have a copy of your files off, if not you can attempt Data Recovery efforts here (if the drive mechanically works)

https://discussions.apple.com/docs/DOC-3172

Likely you will have to take it in to have the drive replaced

https://discussions.apple.com/community/notebooks/macbook_pro?view=documents

leonel junior wrote:

I hold the optiom key, before press the power button.

Should I do it after startup tone ?

Thanks!

Yes and also read my post regarding running AHT, there is a link to an Apple bulletin that will explain how to run AHT, remember to run it in Extended Mode. But i agree you probably just need to take it in for service because the HD is dead. Hopefully you have been using Time Machine or another backup scheme, once you're back on your feet you can restore from the backup.