You need to provide more information please.
What type of wireless card does your laptop have? Does it support G, or N?
What version of Windows is your laptop running?
What is the specific model of the router? Does the wireless router support Wireless G, N,?
Have you tried updating the routers firmware to the latest version?
What mode is the router operating in? Mixed? G? N?
What security scheme are you using? WPA, WPA2, WEP?
What frequency is the router set to?
What channel is the router set to?
How far away is your laptop from the wireless router? How many green bars is it getting?
How often do you get your connection dropped?
Have you tried unplugging the router and your modem and then plugging them back in?