Windows 7: How to slow down WiFi connection?

I'm getting annoyed with my sister because she uses too much bandwidth on her laptop than I can get, he uses facebook, twitter, youtube, and uTorrent at the same time and I'm only using YouTube, visiting forums and playing games. How do I slow down the wifi speed so I can make her internet usage more pain in the ass?

depending on your router, it should have some kind of throttleling control in the admin interface, your just going to have to look for it.

Also it depends one what wireless signal is being used...G or N that the hardware devices are using.

Example 1: Router has wireless N = 300mbps, and laptop 1 has wireless N, so you get a faster transfer speed of data up to the 300 mbps in theory.

Example 2: Router has wireless N = 300 mbps and laptop 2 has wireless G (G supports 54 mbps) you get the slower transfer of data at the G rate of 54 mbps.

Which could explain the differences in speeds between the 2 laptops.

She owns a laptop while I own a desktop pc.

Its hard to determine without knowing what kind of router your using to determine weather it has QoS service in it.
I have the same problem as you with our 11 year old, PS3, youtube and our Iphones\ Ipad. It bogs me down very quickly and gets annoying very fast. Using the LAN ports and Mac addys I QoS'd all the devices and now I can do my own thing on my comp with the PS3 playing COD and my wife upstairs streaming into her IPad, unlike before all I could do is enjoy the lag because they were hogging all the bandwidth.

Here's a pic of how I set up the QoS in my netgear R6300 router and it works damn fine.

Weaken the wireless signal to slow down the connection speed.
Perhaps block it using metal foil.