Windows 7 ad-hoc networks IP problems

I am using Windows 7 home premium for a while and from the beginning I'm experiencing a problem with the ad-hoc peer to peer or computer to computer wireless networks (able to share internet). The problem is that when everything is set up to automatically obtain IP and DNS servers the computer registers on the network but without network access and of course without internet access too, after that I set up my IP manually and everything is ok, but the next day manually written addresses won't work and it successfully obtains an IP address. Is it a bug in the windows 7 home premium edition or there is a bug in my laptop wireless card ??
