My macbook air doesn't read the start up disk

Hello, please I need help.

Im a mac user for a while, can't say that I'm an expert but after some time using mac I got relatively used to its environment, however last week i experienced something that is out of my knowledge skills and I'm going crazy trying to solve it.
I was using my mac and it froze, stupidly i turned it off by pressing the power button, next thing that happened was that the only thing showing in my screen was a folder with an interrogation sign.
After going through internet I read that the problem is that my macbook is not reading the starting disk and that i needed to reinstall the Lion OS.
Problem: I don't have a back up of my computer, my main concern are photos and music and couple of files.
According to what I found out, it is possibly that I start the computer with an external version of the Lion OS stored in a flash drive and then I can access the computer and make a back up.
OK, sounds a bit complicated but i think i can manage. According to my research i can download and save the Lion OS on an external flash drive by buying it from the App Store.
The question is: can I buy it on another mac and create the external version without damaging the OS on the computer from which i will be creating the version for flash disk?
I really don't know what to do, and I've been dealing with this with over 10 days.
Any help would be highly appreciated.
Many thanks!

Carlos.

CarlosAlvarez said:

The question is: can I buy it on another mac and create the external version without damaging the OS on the computer from which i will be creating the version for flash disk?

Click to expand...

Yes you can. When running the installer, be sure you select the correct drive. As a word of caution... you should, as ALWAYS you should, have a backup of that other Mac made in advance in case you do something wrong.

The great thing about Lion is it always includes a recovery partition.
At boot up hold the option key untill the recovery partition is shown.
select the recovery to boot from. Once in recovery select your language
then choose to repair the disk using disk utility.
select the disk to repair and let it go.

I forgot to mention also make sure you select the volume you want to repair the name of your boot drive partition

Hi!
Thank you life and thank you dawson.

dawson1112, thing is, after i pressed the option key, it appears me internet recovery, i join a network and then on the left panel there is no the start disk to select it, and the verify and repair disk options are not available. Any ideas?

CarlosAlvarez said:

Hi!
Thank you life and thank you dawson.

dawson1112, thing is, after i pressed the option key, it appears me internet recovery, i join a network and then on the left panel there is no the start disk to select it, and the verify and repair disk options are not available. Any ideas?

Click to expand...

It sounds like the drive has died. How old is this Mac? Is it still under warranty?

Unfortunatly it sounds like the reason it froze up to start with is that the drive failed.
There are only a few reasons you get the ? folder at startup
One is the drive has an unrecocnizable boot partition
two is the cable that connects the drive to the board is bad or came disconnected ( highly unlikely )
three is that the drive has failed and is no longer recognized in the system. ( most likely )
You should still be able to see the drive when you press the option key , if not that means the drive is dead.