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Windows 7: Cannot open Security Essentials or Windows Defender

11 Oct 2011   #11
Microsoft MVP


You can try the Repair Install first but I'd still back up everything externally.

Look over these steps to get a Perfect Reinstall.

My System SpecsSystem Spec
13 Oct 2011   #12

Windows 7 & Windows Vista Ultimate

One other option you can try prior to the Repair Install is to Submit a support case online for Microsoft Security Essentials. Select "Installation fails" > your country > E-mail Support.
My System SpecsSystem Spec

 Cannot open Security Essentials or Windows Defender

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