Aspect/Image problems with PS3/Monitor

[Mullins]

I am having an odd problem with my PS3, I have a 1080p monitor (BenQ FP241W) which I connect to the PS3 with a HDMI cable, I have set 1080p as the output resolution on the PS3, but there are black bars at the left and right sides of the picture all the time in the menu, playing games, and watching Blu-rays.

I haven't used it in a while and I only recently updated the firmware to 2.70 (then 2.76 yesterday). I'm sure it didn't do it on the older firmware I was using, but I don't think I can go back to it.

I have tried resetting all the settings to default and running video setup again, but it doesn't seem to take effect.

My monitor is set to display the picture 1:1 and when I play a blu-ray on the PC it fills the width of the screen, yet when I put it into the PS3 it doesn't fill the width of the screen.

Has anyone else come across this or know how to fix it so the PS3 actually outputs at 1080p?

Help please