Windows 7: Very sudden internet speed loss - win 7 related

2 days ago I was downloading a game off of Steam when I noticed that the download had stalled. I reset my router as it occasionally goes a little strange and stops processing data. This didn't help the issue. I checked the internet connection on another PC and it is fine. I checked the cable to my pc by using a laptop and the wired connection also ran fine which to me indicated it was not a fault with the cable or router. To test any issues with the NIC I have reinstalled drivers and tested with multiple OSs. The internet runs normally on both Linux and Asus Express Gate.

Putting it down to an issue within Windows 7 I have since tried the following :

Reconfigured MTU, reset network stack, reinstalled drivers, tried an alternative NIC, disabled IPv6, running in safe mode and finally a system restore. None of this has given me any joy.

This is on Windows 7 Home Premium 64bit, my motherboard is a Asus PT6 with an onboard "Realtek® 8111C, 1 x Gigabit LAN Controller(s), featuring AI NET2". CPU is an intel i7 920.



Does anyone have any other ideas I can try?