Tryin to run 2 monitors. Please help

[Numbnuts]

Ive bought me a new monitor so im now tryin to run the pair. Problem is, when i boot up it shows on screen 2 then jumps to 1 when windows kicks in
can you help with this prob
Thanks

 

[Numbnuts]

If i swap the ports at the back it shows my main screen as screen 2 though

 

[Numbnuts]

Sorted it, windows was seeing it as right but it wasnt. I had to swap ports but leave the second one out and reboot. Then i reinstalled the drivers for the main monitor and windows saw it as the main monitor then, in the new port. I could then connect the second monitor and all was well.
The problem was because ive always had the main monitor in the wrong port (before i bought the second one if you know what i mean)