iMac 2211 3,06 with Nvidia 8800 fails to boot
Since a few days my iMac hasn't been feeling too well. I don't know how it happened, shut it down on Thursday and it failed to boot up on Saturday.
At first: when you started the iMac screen went black (you could see the backlight on), you heard the chime, 2 seconds of nothing, chime, 2 seconds pause, chime, ... No white screen, no logo, no nothing.
Now (after trying smc and pram reset), it's similar but different. Now it starts, you can see the screen lighting up, chime, white screen with logo, circular thing moving (I can also head the hard drive reading, normal sounds no "ticking"), and when it's about to enter OSX it restarts by itself.
At some point in time I also got a message that my iMac has been restarted or something, only seen it once.
After this and some reading on the web, I opened up the front to take a look at the indicator LED's. As far as I can tell they're all good (all green).
I also tried booting off a CD (linux), it showed one line of the starting up screen, then it stopped, hung, and showed one single red rectangular box (1 letter size) on the screen.
I tried booting of the snow leopard install USB stick I got, this also hung and auto restarted.
At times (not always, but probably around 50% of the time) when powering it up, as soon as the white background shows, I can see a somewhat distorted (should be white but has random pixels in it) line spanning the entire width of the screen, it's probably about 0,1-2mm thick and is always situated at the complete top of the screen.
I was guessing it's the videocard (nvidia 8800), but I'm not sure because the LED indicates it's good.
Initially I thought it was the HD, you know it's always the HD, and after 6 orso years not surprising, but I should be able to boot of USB/CD when it's the HD, no?
Thoughts? Comments? Suggestions? Everything is more then welcome.
PS: also tried booting with 1 memory module (normally uses 2x2), but no difference.
Added 2 pictures taken in verbose mode