How to Fix an Invalid Partition Table

All computer data is stored on drives, most commonly hard disk drives. These drives are divided into sections called "partitions." Most computers have one partition per hard drive. Each partition is treated by the operating system as though it were a separate drive. The properties of each drive's partitions are stored in a special file called a "partition table." If the partition table is damaged or missing, the drive will not function properly, and if the drive has the computer's operating system installed on it, the computer may not boot. Follow these instructions to access Windows 7's built-in partition repair tools.


Instructions

1. Disconnect or remove all removable or external drives.
2. Restart the computer
3. Wait for the BIOS status screen to appear. This will either be the logo of the computer manufacturer (such as Dell) or a black screen with white letters with many technical details.
4. Press and hold the "F8" key as soon as the BIOS screen disappears. This will take you to the Windows "Advanced Boot Options" menu.
5. Select "Repair Your Computer." The Windows 7 Recovery Environment will load.
6. Select your keyboard layout from the drop-down box.
7. Log in using an administrator account, if necessary. The "System Recovery Options" windows will appear.
8. Click "Command Prompt."
9. Type "bootrec /fixmbr" without quotation marks.
10. Wait for the process to finish and restart the computer to see if it worked. If it did not work, repeat steps 2 through 8, then continue to the next step.
11. Type "bootrec /fixboot" without quotation marks at the command prompt.
12. Wait for the process to finish and restart the computer to see if it worked. If it did not work, repeat steps 2 through 8, then continue to the next step.
13. Type "bootrec / RebuildBcd" without quotation marks at the command prompt. If this is not successful, it's likely that the disk is not recoverable and you will have to format the disk and reinstall the operating system

Tips & Warnings

If the "Repair Your Computer" option is not available, you will need to obtain a Windows 7 disc from the computer's manufacturer. Alternatively, you can download the recovery disk image file from the link in "Resources" and burn it to a blank CD on another computer.