Windows Vista has a new feature that allows tuning of wireless networks (autotuning). Unfortunately this can lead to connection problems to with older routers that don't understand the commands that are being sent. If you are using a router in a public location (coffee house, hotel, restaurant, etc), chances are that it's not the newest technology and the tuning can lead to problems. Also, maybe your home router is several years old. In these cases, turning off the autotuning can sometimes improve your wireless connection if you are using Windows Vista.

To turn off the connection tuning, open a command window with elevated privileges; this is done by going to the start menu and typing cmd, but instead of hitting Enter to launch the command window, Control + Shift + Enter.

Once the command window opens, type the following and hit Enter:

netsh int tcp set global autotuninglevel=disable

After the command prompt comes back, you need to reboot for these changes to take effect. If you want to turn the autotuning back on, rerun the command from above but replace "disable" with "normal".