web pages are completely blank

Some of my web pages are completely blank with no error message in it. Also
yahoo messenger and msn messenger pane does not show the incoming or outgoing
message I send. I can see what I typed but as soon as I enter it it
dissappears. Microsoft help and support page won't show anything on the page
for instance when i click the link in control panel. I can find it through
google. my user accounts page shows a blank page. My search companion shows
nothing for a search area just a dog waiting for me wagging its tail. Maybe I
have a virus or accidentaly deleted something. I had problems in search and
web pages then yahoo and msn messenger much later. Hmmmmmmm

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I The Stumped User