iMac 2008 screen lines...

I don't reboot or shut down my machine very often and am usually away from the pc when it boots up.

Yesterday, while restarting my machine, I noticed there are 4 very faint yellow/white lines each about 2cm thick on the right hand side(non ODD-side) of my pc.

Is this a common occurrence in the late 2008 models? I've had the machine for 3 years now, but I'm a bit disappointed with this.

Have any of you experienced anything similar? Like I said, extremely hard to notice it while I'm working with many windows open, but when you "make the entire screen blue" it's noticeable.