macbook air won't boot up

Try a Safe Boot by holding down Shift between the startup tone and the logo/pinwheel.

Regards

The hard drive is probably dead. I am experiencing the same issue, see below.

Spare yourself and BUY ANOTHER COMPUTER if you can financially afford to do so, NOT AN APPLE / MAC.

I purchased my first Mac previously having been a PC user about two and half years ago. I received a defective Macbook Air that has had nothing but problems from day one. So far it has had 3 logic boards, 2 hard drives, 2 top covers, 2 displays, etc. I have suffered through 3 major repairs and am not confident in the machine that I currently have. I have been denied supervisors and ignored by two Sr. Representatives. I have been read to from a poorly written script and feel that no one at Apple including the Customer Relations department cares about me or is interested in upholding the Apple Care Protection Plan which stipulates that I will get a new, working unit if the one that I have has major manufacturing issues. The latest mishap has cost me critical data and ruined a year-long project that I have invested the past five months of my life into. The "authorized retailer" still has my MacAir along with my sole external hard drive, even though they have reported the status as "repaired" to Apple. I have not been offered anything to compensate for the lost of my data, time, gas, wrangling rides or period that I have not had access to a computer. Furthermore, the authorized retailer (Core Mac in Rochester, NY) looks like it is inside a dirty, abandoned building and I do not feel confident that the computer will be usable after receiving it back from them. Apple is not a company that I feel fairly represents its products or customer service. They do not stand behind their products and do not care about the billions of dollars that they make in revenue off of starving artists like myself each and every year. Does any one know how to contact Jobs or Wozniak directly? This situation is out of control! I am devastated.

very sad to read this!

I have the same problem and tomorrow is the 4th time I come to genius bar!

They can only reinstall the system and very soon the problem occurs again and again!