Improving wireless connectivity in Windows Vista & performance of p2p applicatons:
1) Start menu> Type cmd >right click and run as administrator
netsh int tcp set global autotuninglevel=disable
This actually disables autotunning feature which might be unrecognized by your router.Helps in using threading network applications.
is you want to re-enable this feature USE
netsh int tcp set global autotuninglevel=normal