Did it work correctly previously? If so, what has changed since then? If not, try up[censored] firmwares on the NIC and the router/switch. Also, are you running vendor-specific drivers or generic drivers for your NIC?

1) it did work correctly previously, but with an old 10Mb/s hub
 
2) as it didn't work I tried re-installing windows, but that didn't help
 
3) originally used drivers with WinXP, but then tried the drivers on the website
 
4) router/switch is brand new and works with a sony laptop and three other desktop computers, all with completely different configurations, so i am guessing its this card
 
only thing I haven't tried is up[censored] the BIOS of the motherboard and I am usually slightly wary before doing things like that
 
I think this is a hardware problem!
 
PS Have ordered a nice new 3com NIC which should then make things work - i.e. I give up ! However would like to know what the problem is.....

Something easy to test is the cable. Have you tried a different one? How long is the run? I assume it is a cat-5 cable, but I have had problems connecting with long runs. (over 40').

yeah i thought of that, have tried a really short cable that came with the router, a longer one that I had lying around and a really long one that was hidden in a cupboard.
 
no luck
 
and those cables all work with other computers
 
now you can see why this is really niggling...

Have you tried another port on the router/switch? I've seen some bad ports. Also, IIRC, cat5 can run 100 meters (~385 feet) with no problems, without a hub, switch, repeater, etc.

fraid so !

Try this, just for the sake of argument...
 
http://support.microsoft.com/default.aspx?scid=kb;en-us;299357
 
How to Reset Internet Protocol (TCP/IP) in Windows XP

Code:

netsh int ip reset resetlog.txt

 
From a cmd prompt.

Outta curiosity
 
Did you pin the speed and duplexing on the NIC?

not sure i understand you. but i did try setting the speed settings manually in the properties dialog in xp

I have a similar problem with a D-Link router with a 4-port switch. Did you ever get a resolution of your problem?
 
Jay