Improving wireless connectivity in Windows Vista & performance of p2p applicatons:

1) Start menu> Type cmd >right click and run as administrator

2)Type netsh int tcp set global autotuninglevel=disable

3) Reboot

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