Do you have Anti-Virus protection?

Pirated copies of Windows will continue to use other free products such as Avast, AVG, Kapersky. List of antivirus software vendors (many free for home use)

...50 to 60 percent [of PC users] ...don't have, or won't pay for, antivirus protection, antimalware protection," according to Amy Barzdukas.^{[17] source: Microsoft Security Essentials - Wikipedia}

...requires validation, which means it won’t be available to anyone using a pirated copy of Windows. source: How good is Microsoft's free antivirus software?

Microsoft's free anti-virus a solid choice for small businesses

How good is Microsoft's free antivirus software? | Ed Bott’s Microsoft Report | ZDNet.com

Microsoft Security Essentials: 1

Microsoft Security Essentials: 2

A bit of history: 1993 Microsoft tries to enter the Anti-Virus arena MSAV - Wikipedia