Page 1 of Wireless network problems

I`ve got an 802.11g wireless ad-hoc network set up between my main pc (cable broadband wired connection) and my new laptop. I have had it running perfectly before, but since a re-install of xp its causing a few problems.
The network has a habit of dropping every once in a while then goes through a process of finding network, dropping network every few seconds until I reboot the pc`s.
The laptop has a problem with internet connection sharing: some web pages take a long time to load or don`t load at all, msn and windows messenger won`t sign in on the laptop.
I`m also unable to share my drives between the networked computers. I have set up the drives for sharing but when you try to map a new network drive it cant find it.
Any help would be great!