resinstall the Game
This is solution work just for XP

Click Start, then Run
In the field that appears, type gpedit.msc.
This has the effect of the policy editor groupe.choise Computer Configuration - Models of Administration - Network - Packet Scheduler QoS.in the right pane, right-click Limit bandwidth service and choose Properties . Spend the limit bandwidth (%) 0.
Warning! On the button must be checked.
At first, your gain will be 20% ...
not sure if it will work or no