Problem with connection to Internet

General Topics
1

I have a DELL laptop (bought 1 year ago) that runs Vista Home Premium for my son. I don’t know what he has done that resulted in very extremely slow connection to Internet.

On the same port of the router, other computers are working fine. How can I proceed to diagnose the problem?

2

Starting scanning with avast to see if there is any spyware active in his computer…

3

Thanx. Nothing found upon scanning but restore to a back date helped.