re 9/11 question pc running slow

[wendilla]

My pc has been running slow and couldnt access dominoes or games and took quite awhile to get pages up..Now I have found that if I don't sign into Yahoo messenger everything is back to normal.Should I uninstall Yahoo Messennger and reinstall it.Yahoo Messenger works fine just cant have it on when I want to go elsewhere.MSN is ok I can sign in there and get to any page.Hope this makes sense and would welcome any replies.