Double Blackberry connected

Hi there,
I have a blackberry 9700 and have just loaded the latest desktop software 5.01 and when I try to link up with usb my current blackberry it always gives me a option of:
Email settings:
Your messaging account is currently configured to use Blackberry (OLd Blackberry pin). Would you like to switch to Blackberry 9700 (New 9700 pin) instead?
I am only using the 9700 and am not using the other one and want to delete the (254DAA15)
Please can you help as I know this is a problem using windows 7 and the latest desktop.
I do not aoto over the air sync emails etc with outllook but connect my sync via a usb. Just want this horrid prob to go away :)
Kindest regards,
M