Imac misbehaving!

Hi Guys,

Just joined this great forum and would like to say thanks for having me.

I also wonder if maybe someone can shed a little light on what's happening to my poor Imac as it seems to be a little under the weather.

1. For a time now the brightness adjusts itself automatically and there doesn't appear to be any way to control it even though it's mentioned in a few places that in "Display Preferences" one can set it to automatic. There is no such setting on mine. The strange thing is that although it has reached full brightness it still tries to increase it and the display graphic at the bottom of screen comes on every couple of minutes. I turn it down cause it's much to bright and it just goes up again. Quite frustrating!

2. Last week I turned on the Imac from cold and it went straight to the Apple Hardware Test screen. I thought that perhaps I'd accidentally pressed the "D" button, which activates this utility, so I turned the machine off and tried again keeping my hands far away this time but it still wanted to be tested. So I ran the extended test, just in case, and after an hour it reported no problems found. I then restarted and it was fine except that all the applications in the Dock were gone apart from Finder and Trash as well as all the shortcuts in the Sidebar of Finder. Today when I turned the machine on it happened again.

Putting back all the application is not a problem but why is this happening? It kind of feels reminiscent of the bad old PC days.

If anyone can help I'll be greatly relieved.
Many thanks,
Jack

Try resetting the PRAM - NVRAM first. LINK If no joy with that, try resetting the SMC. LINK If neither resets resolve the problem, try booting your iMac using your install DVD.

Once booted from the install DVD, go to "Utilities", "Disk Utilities" from the top menu, and do a verify and repair. Also while you're there, repair permissions.

You can also run the extended Apple Hardware Test when booted from the install DVD. That's actually the best way to run that test. See this LINK.

Regards.

So far resetting the PRAM - NVRAM seems to have solved the problem.

Hey, I really appreciate your help. I definitely couldn't have worked it out for myself!

The fact that you were the only who to respond probably denotes that it's not so common a problem. I even asked at a leading repair centre here in the UK and they'd never heard of it. So there!

Thanks!

PS. I was in your fine state of Texas (Houston) just last month on my way to New Orleans. It's quite some place hey!