Fix the Ubuntu boot partition after Windows XP is reinstalled.

Article Title: fixed the Ubuntu boot partition after Windows XP was reinstalled. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.

The day before yesterday, my windows xp crashed, So I re-installed xp and rushed out the original Ubuntu boot Partition Table mbr. But it doesn't matter. Fix mbr.

First, let's talk about the role of mbr: when we start the computer. The computer first runs Power On Self Test (POST), that is, Power-On Self-check. POST checks the overall memory of the system and the status of other hardware devices. If the BIOS of the computer system (Basic Input/Output System) is out-of-the-box, the computer hardware device will be inspected and configured. The computer's Basic Input/Output System (BIOS) locates the computer's Boot device, and MBR (Master Boot Record-Hard Disk dominant Record) is loaded and run. If you only install Windows 98, it is automatically booted to the desktop. If it is Windows XP/2000/2003, the control is handed over to the NTLDR-system loader, And the Boot. ini is called to display multiple menu files. To wipe MBR is to wipe the boot records of the hard disk.

After windows is reinstalled, grub cannot be started because the hard disk mbr is overwritten, that is, grub information in the original mbr is cleared, and linux cannot be guided, at this time, many people may only have to reinstall linux, but in fact they only need to simply fix mbr.

The following describes how to fix mbr:

First, put the Ubuntu installation CD in, and then start. normally enter the installation interface, open the terminal:

1. Input: sudo grub, so it becomes
Grub>

2. First find the boot partition of your ubuntu (that is, the partition of your/boot directory)
Input: find/boot/grub/stage1
After I press enter on the machine, the following figure is displayed: (hd0, 2) hd0 indicates the first hard disk, and 2 indicates 3rd partitions, that is, the partition where the Ubuntu root directory is located (0 indicates the first partition ).

3. Input: grub> root (hd0, 2)

4. Input: grub> setup (hd0)
If successed appears, it indicates that it is successful.

5. Enter grub> quit and restart.

For friends with multiple hard disks, please note that if your windows disk is installed on the first disk and linux disk is installed on the second disk, if your bios is set to start from the first disk, you must set the parameter to your first disk during the above steps. You need to mount grub into the mbr of the boot hard disk. Of course, you can mount grub into the mbr of each hard disk, this is just a matter of order.