BootMGR, the short name of Boot Manager, is a small program that allows multiple operating systems to be booted from the same computer. It's also called a boot loader. So if this BootMGR file is missing or compressed, you can't start your computer normally. What error messages that users usually get about BootMGR:
• BootMGR is missing, please press Ctrl + Alt + Del to restart
• BootMGR is compressed, please press Ctrl + Alt + Del to restart
What you need: Windows Vista or Windows 7 disk
1. Insert your Windows Vista or Windows 7 disk into the DVD player and restart the computer.
2. You'll see the boxes of Language, Time and Currency and Keyboard in the next screen.
3. There are two options in the lower left side. One is "Repair your computer", and the other one is "What to know before installing Windows".
4. Click on the first one: "Repair your computer".
5. Windows will then try to find the installation directory for Vista or Windows 7, depending on what you have.
6. Next up is a screen with a box called Recovery Options. Click the first option, Startup Repair.
You'll see a Startup Repair box with the message "Startup Repair is checking your system for problems…".
7. When it's done, it will prompt you to reboot. If there is more than one problem it may reboot again to continue repairing.
8. At this time, you can plug out the DVD disk, restart your computer and everything should be working normally.
What you need: a system booting program
1. Get a related booting program, which should be a CD, DVD or usb drive (you can't start the computer, so the program installed on your computer does less help). Here recommend Wondershare LiveBoot, which can help to automatically repair the booting failure Windows caused by the missing or corrupted BootMGR. It supports booting from CD, DVD and usb drive.
2. Insert the CD into the CD-ROM of your computer, and start your computer.
3. Choose "Boot from LiveBoot" from the Boot Menu to start your computer. Then Windows begins to load files, which takes a few minutes.
4. When the file loading is finished, Windows starts, and then LiveBoot menu comes up.
5. Then click "Windows Recovery" tab and hit "Boot Files Recovery".
6. According to the instruction on the interface of "Boot Files Recovery", choose the target Windows and begin to scan. If there is only one Windows, you can skip this step.
7. The scan result will reports that the file is missing or corrupted, then start "Recover" to get your Windows back.
8. Then you only need to get the disk off your computer and restart the computer, and the system returns to good now.
By the way, you can also know more fixes on BootMGR missing issue.