Internet Freezes/Mozilla

[johnnydave]

Often, usually when I am using the internet, the computer just freezes for about a minute before going back to 'normal'. Or it acts very slow. This happens at regular intervals (about every 5-10 minutes) and I cannot seem to understand why this happens.

I have downloaded all of the well known spyware removal programs available (AdAware etc) and run them regularly, as well as anti-virus. I keep them switched on at all times too for good measure. however, these cannot seem to root out the virus or trojan which i suspect is behind this. I have had this problem since I started using broadband internet for my home computer. Please help!!!

PS Whenever I add a URL to my favourites on Mozilla the above occurence happens as well. Or as soon as I log onto MSN Messenger, I need to wait a minute or two before I can reply to any of my contacts. WHY????