Estimates vary... here's one: "It's estimated that at its peak Conficker infected more than 11 million PCs globally." -- http://www.sophos.com/en-us/security-

Estimates vary... here's one: "It's estimated that at its peak Conficker infected more than 11 million PCs globally." -- http://www.sophos.com/en-us/security-news-trends/reports/security-threat-report/html-04.aspx http://www.sophos.com/en-us/security-news-trends/reports/sec... Numbers in the range 15-25 million were also tossed around. It's hard to estimate. Steve Ballmer expected the Windows installed base to cross the 1 billion mark in mid-2008: http://www.zdnet.com/blog/microsoft/microsoft-expect-windows-installed-base-to-hit-1-billion-by-mid-2008/596 http://www.zdnet.com/blog/microsoft/microsoft-expect-windows... Conficker peaked around January 2009 I believe. At 10 million that would be 1% of 1 billion.