None of the above combinations works *at* *all*. What now?

Nothing at all! Except the drive swallows the disk, and you can hear it spinning. Nothing appears on screen, and the C key (like all others) has no effect when booting.

One other thing I forgot to mention is that it doesn't matter if I press & hold the key (or key combination) *immediately* on pressing the Power button, or wait a second, or wait until the "chime" sound - no result.

Well, I have no idea :-( but it's possible.

However, even if that was the reason for not booting the SL install DVD, that doesn't account for not being able to get any other boot key to work - e.g. Cmd-Option-R-P is supposed to reset NVRAM... nothing. Cmd-S for "single user mode" - nada. Doesn't make sense.

Thanks, both of you guys

I will try both of your suggestions later today. Now that you mention about trying a different keyboard, I originally tried a generic PC keyboard which didn't work at all. I thought at the time maybe some Macs just might need a Mac keyboard so I switched and didn't think of it again. But maybe there is something fundamentally wrong with the computer... it has been lying in a store-room ofr over a year, and the ex user (I seem to recall) complained about problems but no idea what his issues were.

Anyway... worth a couple more minutes of experimenting, isn't it!

Eustace Mendis wrote:

Try entering Admin as the User name and leave the password field blank. This used to be a default setting.

...uhh, how do you do that?

All I get is an 8-ball & next to that "Grant's Mac", then below it the password block.

If I click "back" the options are Sleep, Restart, or Shut Down. Here "Grant's Mac" is clickable, and that of course takes me back to the logon screen.

I don't see any option to change the logon user name...??

[Ohhhhh... I just spotted that on this screen it tells me it's on Version 10.4.11 but I don't think that really matters does it]

OK, to answer all my own questions then ;-)

- to try logging on as administrator, just enter the wrong password for the default user anumber of times (keep hitting enter on a blank pw I guess) until you are prompted for the "master" unlock password or words to that effect. Hmm well anyway.

That also didn't work BTW, no default passwords were set on this machine.

- the problem was the keyboard, but not a faulty one: a later model one. The computer was running 10.4 and has / had older firmware which didn't recognise the newer slim aluminium keyboard...I took it in to my local guru bar and they found one of them old chunky curved models which worked first time. Used that to reset the user password, and once i got it home I was able to use the System Preferences -> Startup Disk app to boot it from the Snow Leopard install DVD. Yayyyyyy....

Thanks to you guys for your helpful suggestions - if it weren't for people like you we'd all be floundering helplessly! Hip-hip - Hooray 😁