New Email

I have logged into two different email accounts on the same computer, using the same browser. One has adverts at the side, the other does not. Looking at the image below, the upper account is a hotmail.co.uk and the lower is a live.com. The only difference I can think of is that somewhere in the settings for the hotmail.co.uk account there is some sort of 'approval' to show adds.

If this is this case, how do I disable this? If this is not the case, how do I get rid of these annoying adverts? It must be possible, as the lower account in the image never shows adverts.

Any help would be greatly appreciated.