Borders appearing on new images

I've been using PS and IR for about a month. I was using PS and opened a new image with a blue background color. When I opened it, it had a dark blue border. Why? And how do I reverse this?

I've opened new images File>New......all the time and this has never happened before and it's frustrating. Such a small thing but..........

Any help would be much appreciated.

can you do a screen shot of the options on the new dialog box? I'm not familar with anything that causes this, it does sound a bit strange, but if you scan do a screen shot, then i can try and reproduce the problem.

Thanks but I no longer have that problem.