Master Boot Record

Q:
I must have done something to my computer somewhere along the line, because every time I restart my computer (with Windows XP), I get a “MBR Corrupt” or an “Error loading operating system” error message. What do you think I did and how can I fix it?

A:
Very good question! These errors could have started from a number of things. If you were trying to remove spyware from your computer, you could have triggered something within your system that started these messages. Anytime you work in detail to try and get a computer problem solved, you take the risk of hindering something else. And although these error messages may seem like the end of the world, they’re really not!

If these errors are the only ones you’re getting, it’s probably pretty safe to say that your hard drive is still intact and able to work properly. In this case, it just seems like the Master Boot Record (MBR) is damaged, so we just need to work on repairing that.

Before we go any further, let me give you a little information on the MBR. When you start up your computer each time, the BIOS searches for the MBR in your hard drive and the MBR then tells the BIOS which partition of your hard drive holds the operating system. Therefore, if the MBR is damaged, it’s unable to respond back to the BIOS, resulting in a lost operating system. If you have this problem, you may see other error messages like “Invalid partition table” or “Missing operating system” along with the other two from your question.

Now, let’s move on to repairing the MBR so you can get things back to normal. For this, we will be working with the Recovery Console in Windows XP.

First, locate your Windows XP Setup disk (it came along with your computer when you first got it). Then restart your computer with that disk in your CD ROM drive. This will keep your computer from booting into the hard drive like it normally would.

Next, you’ll see a prompt to press the “R” key, which will bring up the Recovery Console. When that starts, you’ll receive another prompt asking you to enter in a number that corresponds with the Windows XP installation problem that you’re repairing. This number will more than likely be 1 (one). This is usually the only choice as well. Make sure you do enter a number, because if you leave it blank and just hit Enter, Recovery Console will quit and your computer will just restart normally, with no errors fixed.

So, once you enter in the number 1, hit Enter and you will then be asked to type in your administrator password. Hopefully you have it memorized or written down somewhere, because you must have this password to continue.

Now, the next section will be the Recovery Console command prompt. Once there, type in “fixmbr” (without the quotes) and then verify that you want to continue. When you do that, your damaged MBR will be replaced with a complete new one and you should be able to restart your computer normally from now on. If you’re still having trouble, you may also need to fix the boot sector. If this is the case, just follow the directions above exactly, but type in “fixboot” when you get to the Recovery Console command prompt.

Another thing to keep in mind is that if you have more than one operating system, you may have trouble following this tip. If so, you may need to do some additional reading on the “fixmbr” and “fixboot” repairs to find out how to you should proceed with this tip.

~ Erin

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