I just finished reading an XP book
Start - run - type gpedit.msc
Expand the "local computer policy" branch
Expand the "administrative templates" branch
Expand the "network branch"
Highlight the "QoS Packet Scheduler" in left window
In right window double click the "limit reservable bandwidth" setting
On setting tab check the "enabled" item
Where it says "Bandwidth limit %" change it to read 0
Start - run - type gpedit.msc
Expand the "local computer policy" branch
Expand the "administrative templates" branch
Expand the "network branch"
Highlight the "QoS Packet Scheduler" in left window
In right window double click the "limit reservable bandwidth" setting
On setting tab check the "enabled" item
Where it says "Bandwidth limit %" change it to read 0