Extended Desktop/mouse disappearing problem...

Hi,

I have an issue that results in the following, both when the laptop is being used independently and when on a base station and monitor.:

1. The mouse pointer disappears off the edge of the screen (left only).

2. When I do a 'print screen' I have what looks like two desktops:

I have researched this and it seems this commonly to do with dual monitors being set up, but I have checked this and this is not the case for me. The 'display options' only finds one, and pressing windows+P confirms that it is set up as 'Computer Only'. 

It is as if I have pressed something accidentally, or something is overriding my laptop.

Any help would be appreciated, as this is driving me nuts!

I have an NVIDIA graphics card and I also use Citrix Remote Desktop occasionally.

Thanks.