Why torrent client is killimg the network and itself ?

[cass]

Hi, I've been happily using torrent clients for few years now , but what I see for past couple weeks is beyond my experience, so hopefully somebody can help:

Symptoms are: every time I start torrent client everything seems to be fine at the beginning. It gets exepted download and upload speeds and all indicators are happy green signs. But after a while (couple minutes most) speed goes down to around 0,5- 1 kb/s and stays there (sometimes dies to 0 ). At the same time, when this happens my local networks gets killed as well: no other program can access Internet services, LAN does not work, wireless switches off. Same symptoms can be seen sometimes even if all downolads/uploads are stopped and program remains idlle. Funny think is, that indicators remain green, when all this dissasters happen. After closing Vuze (and sometimes rebooting the router is needed) network goes back to normal...untill I try to start torrent client again.

This symptoms could not be caused by any recent new program installations (none installed, I got it under control) unless Windows update did something in the background

What I did already to try to solve the problem:

reviewed all the advices and tricks related to speed and network issues

changed torrent clients (tried Vuze, BitTorrent & uTorrent) and used all the trick and tips they recomend on FAQs & Forums

changed n/k card, n/k cables in my PC (I'm using Ethernet connection)

changed router from Linksys WAG54GX2 to D-link DSL 2740B (none of them is on list of bad routers)

checked my ADSL service (downstream speed 7456 Kbps) at http://broadband.mpi-sws.org/transparency/bttest.php and my ISP provider (TP SA in Poland) - everything OK there

I'm using Windows XP, Norton 360 (checked that one, olso seem to be OK)

And now I will very much appreciate any usefull advice, how to solve the problem as I ran out of any more ideas...