How do I know if a pixel is dead or stuck?

[Denman007]

I can see the bad pixel on a white, green, and yellow. Looks fine on a black, blue and red background. (using DPT.exe pixel tester)

 

[Nodsu]

It's a "stuck" pixel - the green is not working.

 

[Tedster]

there are public domain software out there that can attempt to "unstick" pixels. It's dicey and may or may not work, but it's worth a shot.