BBC.com reports that Microsoft is warning Windows users about an email virus that contains a “poisoned” PowerPoint presentation. The virus contains an attachment that if opened, installs keylogging software on the infected machine. Microsoft says it could be weeks before a patch becomes available. The security loophole has been found on PowerPoint 200, 2002, and 2003. The virus comes from a Gmail address and has a slide show attachment that purports to be a humorous slide show about love between men and women…