Could we first try to reset your PMU by removing the battery and power adapter, Then hold down the power button for 30 seconds then connect the power adapter and try to power your mac backup.
Let us know what happens.
Is it pure white (No Icons or anything ) and does it happen as soon as you turn the machine on?
In that case it is looking for the drive with the operating system on it, Could you shut your machine down and the power it back up, As soon as you have let go of the power button could you press and hold the Option key (alt key to the left of the applekey) and hold it till the load selection screen opens.
Once te selection screen opens could you click on your OSX drive and click the right hand arrow.
If that does not work let us know if you have your OS disk.
So the Option key did not work?
Is that correct?
Before we try the first aid tools could we try a safe boot.
Shut your machine down and the power it back up, As soon as you have let go of the power button could you press and hold the Shift key and hold it till the load icon shows on the screen, Then let go and wait up to 30 mins for it to load into the Safe Boot login screen.
If the Safe Boot login appears could you just restart like normal using the button at the bottom of the screen.
If that does not work could you put your OS disk in the machine and power it up, this time press and hold the C key till the installer menu opens, Then go through the menus till you get to Disk Utilities and choose First Aid.
Follow the prompts to have first aid check your OS drive.
Let me know how you get on.