windows live messenger

[madcaplost]

All users on our computer have the messenger service automatically come on
and then goes through all the contacts and opens up conversation windows.The
computer then locks and you cant use anything and then have to reboot the
computer.I have scanned for viruses and spyware but there hasn't anything
been found.Hope anyone can help because it is such a pain and the kids
haven't stopped moaning..many thanks
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cya