This was....unusual

So I have a 21 inch iMac that is a little over 1 year old. A few months ago it developed a 1 pixel line about 1 inch in from the right screen edge.
I figured, what the heck, I can live with it. It's not that bad.
This morning it disappeared - as I was looking at it. Weird, to say the least.
I know it was hardware related because it didn't show in screen shots.
So, anyone have any bright(ish) ideas? What are the chances it'll come back? Or worse. Could this be related to my runaway fan problem (not due to overheating, I checked - different thread to come)?

cradom said:

So I have a 21 inch iMac that is a little over 1 year old. A few months ago it developed a 1 pixel line about 1 inch in from the right screen edge.
I figured, what the heck, I can live with it. It's not that bad.

Click to expand...

I wouldn't have dismissed this issue so easily. A 1 pixel line could be the warning sign of something worse to come.

I know that you mentioned that this iMac is over 1 year-old...but if you have any Applecare remaining (extended Applecare)...I'd get Apple to look at it ASAP! If you only have/had the standard 12 month Applecare...I sure hope that this problem didn't start BEFORE the Applecare ran out.

- Nick