I have Windows 7 and Windows Live Mail.  My mother has Windows Vista and Windows Mail.  She scanned a document and saved it as a pdf.  She tried to send it to me as an attachment to an e-mail.  The attachment arrived, Expert PDF Reader opened it, but it was blank.  I tried to research why it was blank and informed that my security settings kept some attachments from opening as a security measure.  Where do I find my security settings and what do I do to open my mother's attachment?  Is there anything else I need to know about this issue?  

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