PC Freezes temporarily on connection - please advise?

I have been having problems for the last month with my PC 'freezing' for 5 to 10 minutes after connecting to the Internet (Adsl) and I have had a lot of help from **Chaslang** in your Malware Forum. We have checked through all the Malware /Spyware possibilities and done an AVG Anti-Rootkit check. No problems have been found and he suggested trying another forum for help.
Original Thread was "Klone Virus Help" if you want to look at our progress?
I have WinXP, 20 GB h/d and connection is 256kbps. The PC is approx 1 yr old desktop Dell Dimension 3100.
After I connect, I now open Task Manager to watch for any unusual processes but notice that some are there and then disappear when Internet is available again. I am connected, but ALL programs freeze up.
Can you help out please?
Steve :cry

 

I have now posted this problem in Software Forum, please remove from this forum.
Thanks