MY IP ADDRESS IS THE SAME AS ANOTHER COMPUTER

firstly I am no software, PC, techi nerd so forget me fixing the problem I have only had a BRAND NEW mini laptop with Windows 7 and a vodafone mobile connect device for a few weeks now. I keep getting popups saying another computer has the same IP address as me.
1, I don't know how that is possible.
2 I don't know what a IP address is and 3 the most important, I would not know how to fix it and where to begin. Discuss! Thanks

Stevanbcool@yahoo.com or stevanwarburton@googlemail.com or dionaea@hotmail.co.uk