Fix MBR
"I was trying to fix a spyware problem and it seems I messed up my computer. Now when I start Windows XP, I get the 'MBR Corrupt' and 'Error loading operating system' messages. What should I do?"
Got a Damaged Master Boot Record?
Although those messages sound pretty scary, there's a good chance your hard drive is still intact. In most cases this problem can be fixed with a simple procedure that repairs your Master Boot Record (MBR). When you start your computer, the BIOS (basic input/output system) looks for the MBR on the first sector of your hard drive. The MBR tells the BIOS which partition on the hard drive contains the operating system.
So... if the MBR is damaged, the BIOS can't locate and start the operating system. When your BIOS detects a damaged MBR or boot sector, you'll see ominous messages like Invalid partition table, Error loading operating system, or Missing operating system. In some cases, dark clouds will apppear on the horizon, and you may hear the distant rumble of thunder. But fortunately, the Recovery Console offers some tools to help clear up the problem.
Repairing a Damaged MBR
Your Windows XP setup CDROM has a tool called the Recovery Console, which is designed to help you repair a damaged master boot record or boot sector. To start the Recovery Console and fix your damaged MBR, follow these steps:
- Restart your computer with the Windows XP Setup disk in the CDROM drive.
- If you are prompted to press a key to start the computer from CDROM, do so quickly. Otherwise it may try to boot from the hard drive.
- After a few minutes, you'll see a prompt to press the R key to start the Recovery Console.
- When Recovery Console starts, it will prompt you to enter a number corresponding to the Windows XP installation that you need to repair. In most cases, you'll enter "1" (which will be the only choice). If you press ENTER without typing a number, Recovery Console will quit and restart your computer.
- Enter your Administrator password. If you don't enter the correct password, you cannot continue.
- At the Recovery Console command prompt, type fixmbr and then verify that you want to proceed.
Your damaged MBR will be replaced with a shiny new one, and you should then be able to boot your system normally. In some cases, you may need to repair the boot sector in addition to the MBR. If your system still doesn't boot properly, repeat the steps above, but issue the fixboot command instead.
NOTE: These procedures assume that you have only one operating system installed. If you are an advanced user and have a multi-boot system with more than one operating system, you may need to do some additional reading about the fixmbr and fixboot commands at the Microsoft website.
Do you have experience with a damaged master boot record? Post your comments below...
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Posted by Bob Rankin on June 7, 2006 08:59 PM
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Article information: AskBobRankin -- Fix MBR (Posted: June 7, 2006 08:59 PM)
Source: http://askbobrankin.com/fix_mbr.html
Copyright © 2005 - Bob Rankin - All Rights Reserved
Most recent comments on "Fix MBR"
(See all 93 comments for this article.)Posted by:
Brian 500
09 Sep 2009
You can fix a corrupted MBR with a product called DriveRestore Professional. Run a boot sector analysis and it will detect all the drive errors... the product will then auto-repair the errors for you. It can be downloaded at: www.pcrecovery.com/driverestore
Posted by:
Paul Higgins
15 Oct 2009
I have used fixmbr and fixboot many times for myself and others, usually succesfully.
for those with some of the problems listed above there is an excellent option called UBCD for Windows. (google it- one works for XP, but for vista you need the Vista specific version- google UBCD for Vista). It can boot you into Windows recovery console without the need for a Windows disc. You do need to build the CD and have a bit of know-how, but I taught myself to use it succesfully. It includes many other tools, such as partition managers and recovery.
there are many good guides to explain how to build and burn the CD as there are to use it.
I wotk on the thory that if my drive is innaccessible, and I can't afford professionalhelp, what have I to lose?
Be aware though, if you have critical data any attempt at home recovery can make professional recovery very much more expensive if you corrupt the data further or overwrite it.
Posted by:
Arnab
28 Nov 2009
I have a DELL Inspiron 1545 Laptop with Windows XP SP2 installed in it.I was trying to format a drive using GParted tool.While doing so, i created a new partition table, by mistake. Now it is showing as the entire 250GB as unallocated.I have not partitioned or formatted anything.I guess i have deleted the MBR and the remaining part of the disk is still intact. Am i right? If so, will the solution provided in this article work? If not, what would have happened? Kindly suggest me a solution.
When i switch on the laptop, i get the following error:
"No bootable devices--strike F1 to try reboot, F2 for setup utility.Press F5 to run on board diagnostics"
Posted by:
Mike
07 Dec 2009
The freeware tool "offline nt password & registry editor" can be used if you do not know the administrator password. It is a boot iso, menu-driven, very simple to use.
Posted by:
Dheeraj bharti
22 Jan 2010
Hi my laptop's nvidia chip was changed and so i'd been using my hard drive as an external usb drive. The technician got my laptop to boot with his hard disk. Now when i connect my hard disk back i get only a blinking cursor in the left top corner of the screen. However all the folders seem to be intact when i use the same drive as an external drive on other pcs.
Posted by:
Dheeraj bharti
22 Jan 2010
Hi my laptop's nvidia chip was changed and so i'd been using my hard drive as an external usb drive. The technician got my laptop to boot with his hard disk. Now when i connect my hard disk back i get only a blinking cursor in the left top corner of the screen. However all the folders seem to be intact when i use the same drive as an external drive on other pcs.
Posted by:
Dheeraj bharti
22 Jan 2010
Hi my laptop's nvidia chip was changed and so i'd been using my hard drive as an external usb drive. The technician got my laptop to boot with his hard disk. Now when i connect my hard disk back i get only a blinking cursor in the left top corner of the screen. However all the folders seem to be intact when i use the same drive as an external drive on other pcs.
Posted by:
Rufus
08 Feb 2010
"Seems like it can't hurt..." NO NO NO. It CAN bloody well hurt. FIXMBR is vile because it will destroy partition information and effectively wipe the C drive (which is usually the one with the MBR) clean and you will lose all your files and programs. DONT USE IT UNLESS YOU BUY ANOTHER HDD - COPY YOUR FILES TO IT FROM THE RECOVERY CONSOLE - (EASIER SAID THAN DONE) AND THEN FIXMBR, followed by FORMAT followed by a clean install. 1 days' worth of fun which, if you are not too careful, will cost you your files.
EDITOR'S NOTE: It's extreme to say that FIXMBR *will* destroy your partitions. In some rare cases, it may. But that sure isn't the norm.
Posted by:
Rufus is an Idiot
23 Feb 2010
Rufus you are an IDIOT and clearly un-informed!.
fixmbr does not remove all your freeking file doos - f%$#$!@ing learn more about a commands before commenting next time - idiot!
Posted by:
BlueRaja
27 Feb 2010
@Rufus: The master boot record is not "on the C:\ drive;" it does not belong to any mapped partition. If anything, it "belongs" to the hard-drive itself (sector #0, to be specific)