HI!
Does it say that Windows LIve Onecare has encounter an error and needs to close? It could be a problem with the .net framework that is installed on your computer. You might need to uninstall the .net framework that is installed on your computer and just re-install .net framework 3.5 SP1.
contact support for further assistance on this concern.
Contact support :
http://social.microsoft.com/Forums/en-US/onecareinstallandactivate/thread/30400b52-7f26-4ba0-bc18-17e305329d90
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bayabasgirl29