I have been a given an iMac 24" with a crashed Ubuntu installed on it. I have an install CD of Snow Leopard (not a machine dedicated one). I use a PC keyboard.
How can I install SL onto that machine to replace from scratch the installed OS ?
When I use the combination option-boot, or C-boot, or Option-R-boot, nothing happens... then Ubuntu launches and crashes. I never see the Apple logo.
When I insert the CD into the Mac at boot or before the boot, it keeps it a little time at boot, then ejects it.
EDIT 1
I have rebooted holding command-option-P-R. No display, the Mac makes THE sound, and auto-reboot.
Then I hold the option key: nothing happens, no image onscreen (power button of the screen is blinking), even if I wait 5 minutes. If I release the option key (alt on my PC keyboard, the Windows key should be the Command one), nothing more. If I then press the power button on the Mac, it shuts down instantly.
If I then reboot in a normal way, Ubuntu launches and crashes as usual.
TIP : I use a Dell 27" screen.
EDIT 2
I've burned a linux boot CD onto my W7 x64 PC (Ultimate Boot CD), inserted it into the booted Mac under crashed Ubuntu (no ejection of the CD, the drive tried to read things onto the CD), Hard reset, then kept the C key during boot. The CD drive did not tried to read the CD (no sound), and Ubuntu started/crashed as usual.