iMac will not boot up

Hi, I am new to Macs after many years with PCs. I have an older iMac (white plastic) updated to Snow Leopard without any problems until now. It froze whilst downloading latest iPhone update through iTunes last night. I forced a shutdown with the button on back of screen.

Today, it will not boot up, help!

After pressing the button, it chimes, then grey apple logo and spinning ball. At that point I get a strange screen, see picture.



I have tried starting in safe mode and it runs without probelm, although there is a pattern beneath the cursor.

Can someone help please?

Have you been using Time Machine to make backups? If you have, try restoring to a point in time before you downloaded the iPhone update. No backups? Run the Apple Hardware Test. Let's see if it indicates what's not working.

No back ups, ha. I shall follow your suggestion and come back with the result, thank you.

Mmmmm. Well, attempted to run this test. Machine will only run in safe mode, which means that with the required restart from the installation cd, the computer will not restart! There is just a constant noise from the cd drive.

No backups? Well, I'm not going to beat you up any more than you're already beating yourself up, but basically it's time to take that machine to an authorised Mac tech and hope for the best.

Sorry, been away for a few days. In safe mode I can back up any files and data I need, but I can't obviously restore to a previous date.

So are you saying that in safe mode the computer works normally and doesn't have any graphic glitches like what you photographed?

It works in safe mode, but not quite normally. There is a faint shadow by the cursor, please see below.



I reinstalled the operating system, but the screen is as before. When I started it again in safe mode, I found that videos on the Apple website just show as plain white, see below.



Whilst browsing the 'net, the computer locked up again, just as it had when the problem first started.

I think it's time to follow chas_m's advice about taking it on in to an authorized Apple dealer or Apple store and have them diagnose it for you.

Yes, I must agree with you. I will keep you informed

Yeah, I think the video card is pooched.

Shows my age doesn't it? I actually had to google "pooched", though I obviously understood what you were getting at! Ha ha, or should I say lol?

Repaired by local computer repair shop (not Apple). It was the graphics card/logic board connections, I think caused by overheating. I get the impression that it's a common problem with laptop type computers? Anyway, he gave it some sort of heat treatment (not re-soldered) and coating which cured the joints. Works fine now. Considering the price of a replacement card/board, I was pleased with £85.

Oh yeah, that's not too bad for an older out-of-warranty machine.

Sorry, "pooched" (and the often-used "hooped") are Canadian idioms. I'm slowly becoming one.

Glad it's back to normal!

Good "talking" to you Chas

Regards
Ian

It's gone again! Think I'll stick with my PC

It's happened again, that fix didn't last long!

Sorry to hear that. Time to find a better tech -- or talk directly to Apple.