The steps off QoS in Windows XP and Windows Vista (make sure the status of your account as an administrator):
- Click Start > Run
- Type "gpedit.msc" in the box, Then press enter
- In the Local Computer Policy, click the plus sign on the Computer Configuration, then click again on the Administrative Templates.
- Click the plus sign on Network and select QoS Packet Scheduler
- On the right side of the box, double-click on Limit Reservable Bandwidth
- On the Settings tab, select Enabled
- In the Bandwidth Limit% box, replace the contents to be 0%. (Don't leave blank)
- Click and restart your computer