The QoS Packet Scheduler is a bandwidth monitoring device. It'd only be on your computer because it's an XP only feature and wouldn't be on your old one if you had a different version of Windows and not on your friend's if he has a different version of Windows.

Either way, the packet scheduler only really affects LAN connections and shouldn't have an effect on internet connection. Which is to say it'd play a part in internal network bandwidth speeds and connections but in traffic coming to and from an ISP - your actual internet connection - it shouldn't do anything.

So I don't think that'd have anything to do with it. You can disable it anyways, if you'd like, and it shouldn't necessarily have any negative effects either. It's something that's sort of... there... just... there. .