iMac (early/mid 2006) isn't displaying video

Hiya,
I have an iMac that is turning on (fan makes sound, power light comes on, chime chimes) but the video doesn't at all display. Some other pages I've read stated that it's a lamp while others state that it's the logic board. I'm praying for the former... but if anyone has any further insight, I'd much appreciate it. Thank you!

Does the power light light up then dim out or does it sound as if the thing is powering up and the disk is spinning but the display is gone

Disk is spinning, power light in on and steady. I haven't seen it dim. It's doing all the apparent things it would if working correctly, it's just not displaying a thing.

have you got a mini DVI adaptor cable to DVI or VGA, if you can hook up an external monitor you can find out if its the display or video card that is at fault

More often than not this problem (IMO) is down to the graphics card, which is sadly attached to the Motherboard......I have heard of people replacing these but I can assure you it probably isn't worth doing.....

As said by Louishen, you can hook it up to another monitor and if it turns out to be the screen, you can usually pic these up at a decent price on ebay..........