I.E.8/Mcafee blocking valid certs

hello everyone
could you plse help- I recently started using explorer 8 and more o
less at the same time my ISP provider in the UK switched its onlin
protection to McAfee from Norton.
For some reason now Explorer has started blocking 80 per cent of al
sites even when the certificate is valid. It even blocks access to B
Yahoo! until i authorise download.
Is this a problem of the new net protection or is it an Explorer issu
or do i simply have to change some settings. Getting an answer out ou
BT is virtually impossible.
Many thanks for any help/advic

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Kale
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