'Connection with server was reset' error when downloading files

Hi,
I am having ongoing issues downloading files from various websites using
either IE7 or Safari on Vista Business on a HP laptop. The download gets to
around 8mb and then hangs for approx 2 minutes before the error message box
pops up saying the 'Connection with the server was reset'.
I use Windows Live One Care and have tried turning the firewall off, turning
the firewall off in my router and even set up a second router but always get
the same result.
Colleagues at work can access the same files without issue on XP machines
with One Care installed so as I've tried 2 browsers and 2 routers I'm
thinking the issue is with my Vista set up somewhere.
Any help appreciated.