Open OneCare, click on change settings.
Go to the logging tab
click on create support log
a report will open in your web browser
scroll to the virus and spyware section of the report and you should see the detections and actions taken along with a location.
Are you getting "Quarantine Failed?" If so, see this post for information about Quarantine Failed - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=1548384&SiteID=2
Are the same infections appearing regularly and not being removed by OneCare, although detected? If so, follow the instructions in this post, http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=662566&SiteID=2, to report a virus that is not cleaned by OneCare and to get help in removal.
-steve