Repair Disk problem

Had a bit of an "Oops" earlier on today- accidentally kicked the output connector from the UPS

Restarted and all seemed to be OK but, just to be on the safe side, ran Disk Utility, Verify Disk. It came up with errors and the usual "Restart from installation disk etc".

But it wouldn't restart from the Snow Leopard DVD... you can hear it spin the disk and after a bit the grey screen with the Apple logo appears and there it stalls. Eventually the DVD stops spinning and the only thing I can do is a forced shut-down via the power switch

Ran the Hardware test utility- no problems. Disconnected everything except keyboard and mouse, still no joy. Reset the PRAM and NVRAM, same. Tried setting the startup disk to the DVD, same.

I don't have another Mac with a Firewire connection to try Target Disk mode..

It reads the DVD OK, and comes up with the installation dialog if inserted with the system running, it just won't boot from it

I put everything back together and, before posting here to ask the experts, ran Verify Disk again to note the exact error messages... and there weren't any, it passed the drive as OK

So I don't have an immediate problem, but I'm not happy being unable to boot from the DVD.

Anyone got any ideas before I call support?

(I'm out of free technical support time but still within hardware warranty)

Have you tried cleaning the DVD? It sounds to me like the fault is with it rather than the computer.

Yes, tried that, even tried the DVD from the MacBook and (against all instructions) the 10.5 Leopard DVD. No go

I believe that the iMac will only boot from the DVD that was supplied with it, or a newer retail DVD. So it could still be that the disk itself is damaged. I don't know whether Apple will provide a replacement disk if you explain the problem, but it does sound as if talking to them is your best bet.

You may well have a point there, because I should have three SL disks- one from the MacBook, another when I upgraded the old (still dead) iMac and another when I bought this one.

I can only find two... and I can't find the Adobe PSE installation DVD either. Time to institute a rummage, no doubt I've put them "somewhere safe"

Have you done something simple like running a lens cleaner through the drive? The slot-loaders that Apple use (Panasonic iirc) are notoriously flaky and easily upset by dust (although it is usually writing that gets messed up rather than reading).

But then, I had to get the one on my MBP replaced just before Applecare ran out.

No, I haven't tried a lens cleaner, mainly because I haven't got one

Easily remedied of course, but AEP's point has made me realise that at least a couple of DVDs have gone into hiding, so I'll track them down before I do anything potentially expensive.

In reply to a post by AEP:

I believe that the iMac will only boot from the DVD that was supplied with it

Spot on... found the right disk eventually and it booted a treat, thanks

You'd think they'd at least provide an error message

Still no sign of that blasted Adobe DVD though

They only cost about a fiver!

I thought you were referring to Adobe DVDs at first- a disadvantage of flat mode

I'll add one to the "to get" list, I've never needed one before so just haven't bothered.