My monitor is a Hanns-G 22 inch HDMI. I noticed recently that there's always a bright green dot in the right hand corner of the screen.

Anyone with any idea what it could be?

http://en.wikipedia.org/wiki/Defective_pixel#Stuck_pixel

if it's green(or any color) it's a stuck pixel, if it's black it's a dead pixel.

broken pixel

You can repair it (I did on my screen) with a combination of flashing (you can download this from a lot of websites) and rubbing/tapping it.
I followed a guide similar to this one:
http://www.wikihow.com/Fix-a-Stuck-Pixel-on-an-LCD-Monitor

Oh dear, does indeed sound like a stuck pixel, hope for your sake it's not a dead one, that'd suck! :o

lol it's gone. thanks for the massaging tip :P

I have a bright blue dot in the left hand cornor on my screen.  I have tried everything and it still comes back

I had a red one
MUCH worse I can tell you .. just kept staring at me!