This video shows step by step how to use your copy of Windows 7/Vista on CD,DVD, or USB to repair problems preventing your computer from starting properly. This tutorial shows how to use the Windows Recovery Environment (Windows RE) to repair boot problems. This shows how to address problems related to the Master Boot Record (MBR), Boot Sector, or Boot Configuration Data (BCD) Store”.
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Repair Windows 7/Vista Startup Issues With BootRec.exe [Tutorial]