So foolishly I fully installed elementary OS over Ubuntu earlier from USB.
The install crashed, and the dialogue box telling me this wouldn't close. I could only get rid of this by unplugging the computer from power.
Now when I power my computer on I get the usual grub menu asking if I would like to try elementary or install etc. but whichever option I choose I just get a black screen.
Is there any way out of this hole I've dug for myself?
I should also mention that the computer is an old iMac.
Any help that will stop me getting fired will be hugely appreciated.