Macook Air crashed, and on restart I am getting a kernel page and then the grey Apple logo, and it shuts down again.

Hi Supermaniam,

Welcome to the Support Communities!

The article below may be able to help you with this.

Mac OS X: Gray screen appears during startup

http://support.apple.com/kb/TS2570

Disconnect, test peripheral devices and network cables

Note: "Peripheral devices" refers to external devices other than what came with your Mac, such as hard drives, printers, or hubs that you connect via a USB or FireWire cable.

1. Shut down your Mac. If necessary, hold your Mac's power button for several seconds to force it to power down.
2. Disconnect all peripheral devices such as external hard drives or printers (leave only the display, a keyboard, and mouse connected).
3. Disconnect any Ethernet cables.
4. Start up your Mac.

If you can start up this way, one or more of your peripheral devices (or installed software related to the device) is probably causing the gray screen issue. Connect one device, then restart your Mac to test for the issue. Repeat the process until you locate the device at issue. Check with the manufacturer of the device for support or possible software driver or firmware updates that may be available for the device. Try a different cable with the device if possible (such as a different USB or FireWire cable).

If you are using a desktop Mac with a third-party keyboard and/or mouse device, and the issue still occurs, try starting up with an Apple keyboard and mouse connected instead. Try starting with no keyboard and mouse connected, then connect them after start up. Also, try a different USB port on your Mac.

If the gray screen issue persists with no devices connected, go to the next section (with the peripherals still disconnected).

Perform a Safe Boot

1. Shut down your Mac. If necessary, hold your Mac's power button for several seconds to force it to power down.
2. Start your Mac, then immediately hold the Shift key. This performs a Safe Boot. Advanced tip: If you want to see the status of a Safe Boot as it progresses, you can hold Shift-Command-V during start up (instead of just Shift).

1. Note: A Safe Boot takes longer than a typical start up because it includes a disk check and other operations.
2. If your Mac starts up as expected, immediately try restarting.

If the Safe Boot does not work, or the restart after a successful Safe Boot does not work, go to the next section.

Reset the NVRAM / PRAM

1. Shut down your Mac. If necessary, hold your Mac's power button for several seconds to force it to power down.
2. Reset the NVRAM / PRAM.

I hope this information helps ....

- Judy