Windows XP going to 100% when using a network connection

Hi All,
this append just shows my eternal optimism....no-one over on the winxp forums at MSFT seem to have seen this....

In december a windows update affected my PC...the result is that when using a network connection after some time the cpu will go 100% busy and the machine has to be re-booted or left to stand and do nothing for 15-20 minutes to 'fix the problem' whatever that may be.

The symptoms are clear. When performing some interaction that goes over the network card the CPU spikes to 100% and stays there....the app might be explorer or outlook...anything that calls over the network.

Then, as you kill each process that goes to 100% another one jumps up to take its place.......when rebooting the machine you have to kill process after process to get the thing to shut down...and this can happen between 3 and 6 times a day.

At that time I saw 3 other colleagues suffer the same problem. Each of them couldn't find an answer and so rebuilt their OS from format c:

I waited because I had a backup of my C drive....alas, when I finally got a copy of the backup it had somehow become unreadable....sigh....so I just installed a new copy of the OS under dual boot and I use that now..

However, it might be that someone else might have seen this by now and might have come up with a solution.

Clearly, I think it is something to do with the network card driver or the win xp pro interface to the network card driver......but like I said...MSFT have not been able to suggest any way to fix this problem....and i wondered if anyone else here might have an idea...would be nice to get that OS image usable again.....

Thanks

Peter

dell 8600
2ghz cpu
1gb memory
100 gb hard drive
windows xp pro sp 2
2.5 years old.