[Urgent] Download speeds fall to 0kb/s!?

Happy New Year all,

First of all let me introduce myself and somebody who is moderately literate when it comes to computers. My computer is homebuilt and I can normally find a solution for a problem and fix it myself. However this one completely baffles me.

The problem is that ANY download (with the exception of certain P2P downloads such as Torrents and certain online games) starts downloading at normal speeds until lets say 1% is downloaded, and then rapidly plummets to 0kb/s.

A few pointers;

• I am running Vista Ultimate 64bit, and recently partitioned my HD to dual boot with Win7 Ultimate 64bit however both OS' experience the same problems.
• I have tried to download the files on Chrome, IE and Firefox all with the same results.
• I also have a laptop running XP 32bit which does not experience his problem.
• I used to run Kaspersky with the same issues, but my sub ran out so now using standard windows firewalls, disabling the firewall makes no difference.
• As I have no idea what the problem may be, please let me add that I am using an Nforce Networking controller, which i do not believe is the issue however.
• And my router is a Netgear WPN824v3
• My ISP is Tiscali (whom I do not recommend whatsoever!)

Your help or any guidance would be much appreciated!

Welcome
Lets try to diagnose, first
Try and follow the instructions of clean boot
How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7

Thanks for the prompt response. Unfortunately the problem still exists.
I'm on Win7 at the moment which is a fresh install.

So when you unticked everything for the clean boot, you still ran slow?
If yes
Try in safe mode with networking.

Make sure nic card is up to date.
Note these suggestions
Increase Multithread Download Speed by Disable Vista Auto Tuning on TCP/IP » My Digital Life

Update NIC if no improvement, give this a try
Fix My Computer! » Blog Archive » FIX: Windows Vista - Slow Internet Download/Connection Speeds