Q: MacBook Air Grey Screen Won't Boot

I have a mid 2009 MacBook Air that won't boot past the grey screen with Apple logo and spinning indicator(not beach ball)

The laptop is running Mavericks and is: 1.86 GHz Core 2 Duo/2GB/120GB  Model No: A1304

I do not have any important info on this laptop. I have 2 MacBook Pro's and an iMac which are used for more labor intensive activities.  This is used just for surfing and e-mail.

I have tried to run the hardware diagnostics(depress the "d" key before the grey screen) but it reverts to the grey screen with logo and spinning indicator.

I can access StartUp Manager but it reverts to the grey screen yet again no matter what drive I select.

I can't access Safe Boot.

I have done the command, option, P & R (reset PRAM) but to no avail.

I can boot to Verbose and Single User Mode and I do see some errors but have no idea what they mean.

I can't boot to Target Disk mode.

Every so often, if I let the laptop sit and do it's thing I will hear a voice asking me to select a language and press enter, but the screen remains hung at the grey, logo and spinning indicator screen.

I am not afraid to replace the hard drive, if necessary as this machine has long been out of warrantee.

Any help/input would be greatly appreciated!

Thanks!