imac boots to a blue screen

[maxime0212]

my daughter turned off the imac in the middle of some update (have not idea what update) and now it wil only boot to a blue screen with a black cursor in the upper right corner?!?

 

[jvlog]

if it was a OS update it could have been shutdown wile over righting root files.
i'd try busting out the restore discs and do an "archive and install" of the OS.
all of your files should still be there and the system should be good as new.