Laptop is terribly slow when wireless internet is on.

I got this really awkward problem with my laptop. It has the tendency to go really slow when the wireless LAN is turned on. I only have this problem with Windows XP and Vista runs smoothly without the hiccups.

Today I just reinstalled XP and my drivers thinking there were a problem lying with the set up, however that has not fixed the problem. I am currently on the internet through a wire on XP because of how painfully slow it is going.

So to sum up:

How can I fix my problem of the laptop and internet lagging while on the wireless lan.