Hi, something strange is happening with my pc on some sites.
When i go onto ebay or yahoo i get a message saying that the site's security certificate has expired and i shouldn't go into the site.
This has been happening for about a month now and i think it must be something to do with my pc because these are well known sites that would not have a problem like that long term. Even on this site now, i have a red cross on the phishing filter, and a red circle with a red line through it on privacy report.
I'm using IE7 and xp home, with all the updates.

Can anyone advise me on this please, i'm a bit worried that someone has hacked my pc.

many thanks