转到安装Windows 7的驱动器中（如“F:”），
F:WindowsSystem32> bcdedit /set {default} osdevice boot
F:WindowsSystem32> bcdedit
Windows 启动管理器
Windows 启动加载器
-------------------
标识符 {default}
device boot //修复前是“unknown”
path Windowssystem32winload.exe
description Windows 7
locale zh-CN
inherit {bootloadersettings}
recoverysequence {75c57396-353e-11de-9cee-fd57599631b0}
recoveryenabled Yes
osdevice boot //修复前是“unknown"
systemroot Windows
resumeobject {75c57394-353e-11de-9cee-fd57599631b0}
nx OptIn
detecthal Yes //修复前是“No"