smc 7004wfw wireless router - centrino laptop connectivity

i have recently purchased a smc 7004wfw wireless router, i set it up with my mtnl triband connection wired to a desktop where it works fine but whenever i try to setup a wireless connection with my centrino based laptop i manage to establish a connection which within 2-5 mins gives me a message that the connection has limited or no connectivity... how can i overcome this problem? for the 2-5 mins that it works it works fine but after that is just stops working wirelessly... i hope some1 can help me with this... thanks in advance