Black Screen, Leopard 10.5.2 Intel IMac

[geo6121]

Middle of last month I bought a 20" IMac. Everything was fine up until about 1 week ago when the screen went black. I clicked on the mouse button several times only to have a password box pop-up. After filling in the response, all was fine.

Next, same scenario but the password box didn't appear any more. The only way to get the screen back was by a forced restart.

I turned off the screen saver, set the 2 controls in energy server to off, unchecked the box at the bottom left & put "auto login" to to on the Accounts window.

Problem continued.

Next move was to zap the pram, this was 2 days ago. The screen didn't go black but often asked for my pw. It's now back to its beginning phase which is a forced restart !!

I was told that it was due to Leopard 10.5.2 & am considering going back to 10.5.1

Opinions, suggestions ?

Thanks for any replies,

Geo

[Satcomer]

Sounds like something hardware wise might have gone wacky. So get your system install disks and one of the sound have the words printed on it (in small letters) "Hardware Tests". Boot with that DVD and run the hardware tests to see if anything quit.