Win 7 32 bit intermittent wireless

Hi,
I have just spent an hour trawling through the site to try to find an answer before posting this.

I have just done an upgrade to 7 ultimate from vista home premium
everything works fine and drivers are all up to date
cant get a stable connection to the internet via wireless.
i can see the router and connect fine and the connection itsself is stable but after a short time the network times out. Although the connection is still online and OK.
When connected via cable connection is fine.
prior to upgrade with vista connection was fine via wireless.
Curiously however once i had finished the upgrade to 7, the other laptop in the house showed an IP address conflict with the one i have upgraded to 7. (the upgraded one did not)
I have currently got the IPv6 disabled although it has not made any difference to the performance.
as i said i have been looking at other posts but have not yet found any realistic answers to the problem.
oh and i have re - installed the drivers
although i do think its a windows conflict not a driver conflict.
any advice would be fantastic as good old windows also managed to screw up the back up discs from vista prior to upgrading so i cant roll back to vista... ARGH

What router do you own? Did you assign a static IP address to each computer, or is the router choosing IP addresses automatically (DHCP)? What wifi card do you have in the computer that has Windows 7? Where did you get those drivers, and are they Windows 7 drivers provided by the hardware manufacturer or are they the drivers provided by Microsoft?

hi
router is a belkin wireless g . ver 6001au

the wifi card is an Atheros AR5B91
driver version : 2.0.0.70
I have used both a static IP and router defined ip with the same result
the driver for the wifi has been re-installed to no avail.
Drivers were installed from factory and were not replaced when i upgraded to 7
for reference im running build 7100.
hope this helps
cheers

Use short preamble setting on the router. Beacon interval = 500 msec