How to repair hard drive Windows 7?

Hard drives can sometimes run into problems and stop working properly. This can result in your Windows 7 installation becoming corrupted or not booting up. Thankfully, Windows 7 has some built-in tools that allow you to attempt to repair the hard drive and fix any errors that may have occurred.

In this 5000 word guide, we will cover the different utilities available in Windows 7 that can be used to repair a malfunctioning hard drive. We will also provide step-by-step instructions on how to use these tools to resolve common hard drive errors and get your system up and running again.

What causes hard drive errors?

There are a few main causes of hard drive errors in Windows 7 systems:

File system corruption

The file system is how Windows organizes and keeps track of all the files stored on your hard drive. The most common file systems used by Windows are NTFS and FAT32. Over time, the file system can become corrupted through improper shutdowns, power outages, or disk errors. This can lead to missing or inaccessible files.

Bad sectors

All hard drives eventually develop bad sectors. These are parts of the physical disk that become damaged and can no longer reliably store data. The main causes are manufacturing defects, aging, and physical damage to the drive. Windows will detect bad sectors and attempt to lock them out so they are not used.

Malware/virus infection

Viruses and other malware can sometimes damage or corrupt system files required for Windows to operate properly. Certain infections are designed specifically to attack the master boot record (MBR) of the hard drive and prevent Windows from loading.

Hardware failure

Like all hardware, hard drives can sometimes fail due to mechanical or electrical issues. Components like the motor, heads, or controller board can malfunction, resulting in the drive not being detected or data not being readable.

Logical errors

The file system metadata can become damaged even if the physical drive is fine. This is known as logical damage. It may occur from an improper shutdown sequence or other system issue. Logical errors can prevent files or folders from being accessed.

Common hard drive error messages

When Windows detects issues reading or writing to the hard drive, some common error messages you may encounter include:

“S.M.A.R.T. Status Bad”

This message indicates the drive’s built-in S.M.A.R.T. monitoring system has detected an impending failure. It’s advisable to immediately backup data and replace the drive.

“Disk read error”

This typically occurs when Windows is unable to read data from part of the disk, usually due to bad sectors or hardware issues.


This message indicates the drive containing the operating system could not be accessed to boot into Windows. It usually points to file system corruption.

“NTLDR is missing”

NTLDR is the loader file required to start Windows. If missing or corrupted, this error is shown and Windows will not start.

“Hard drive not detected”

If the BIOS cannot detect the physical hard drive, this message may be shown during bootup. It generally indicates a hardware issue or failure.

How to use chkdsk to check the hard drive for errors

One of the easiest ways to check for file system errors and bad sectors is the chkdsk utility built into Windows 7. Here’s how to use it:

1. Open Command Prompt as administrator

Click Start > All Programs > Accessories, right-click on Command Prompt and select “Run as administrator”.

2. Type chkdsk drive letter: /f

Replace “drive letter” with the letter of the hard drive you want to check. Adding the /f parameter tells chkdsk to fix any errors it finds.

For example:

chkdsk C: /f

3. Restart your computer

Chkdsk cannot run on the drive Windows is started from while it’s in use. You must restart the PC to allow chkdsk to check the drive on bootup.

After scanning, Windows 7 will boot normally again. Check the chkdsk log for results.

4. Review chkdsk log

The log is located at C:\Windows\logs\cbs\cbs.log. Scroll to the bottom to see chkdsk results. It will indicate if any errors were found and if they were repaired.

Using SFC to repair system file errors

The System File Checker (SFC) can scan Windows system files and replace corrupted or missing ones with a cached copy located in a compressed folder at C:\Windows\System32\dllcache.

To use SFC to repair system file errors:

1. Open Command Prompt as admin

Right-click on Command Prompt and select “Run as administrator”

2. Type sfc /scannow

This will start the system file scan. Let it run until 100% complete.

3. Restart your PC

SFC will often require a restart to replace in-use files. After restarting, it may run a second scan to repair any remaining issues.

4. Check CBS.log

The SFC scan results are also logged to C:\Windows\logs\cbs\cbs.log. Check for any reported errors and whether SFC was able to repair them.

Using bootrec.exe to rebuild boot configuration

The bootrec tool can help rebuild the boot configuration if startup files are missing or corrupted. From the Command Prompt:

1. Run bootrec /fixmbr

This writes a new blank master boot record (MBR) to the drive.

2. Run bootrec /fixboot

This repairs the boot sector files required to start Windows.

3. Run bootrec /rebuildbcd

Scans all drives for Windows installations and rebuilds the BCD store with their information. This can detect Windows installations that were not showing up.

Typically running these three bootrec commands will resolve most boot-related issues caused by file corruption.

Using Windows Startup Repair

The Startup Repair utility built into Windows setup can automate many of the system file and boot configuration repairs. Here’s how to run Startup Repair:

1. Insert the Windows 7 installation disc or USB

Boot from the media you used to install Windows 7 originally.

2. Select your language and click “Next”

3. Click “Repair your computer”

This loads the recovery options.

4. Select “Startup Repair” and click Next

This will scan the system and attempt to automatically repair any issues with system files or boot configuration. It may run through several reboots and repairs.

5. Let it run until complete

When finished, remove the installation media and reboot normally. Startup Repair will create a log of its results at C:\Windows\Logs\Srt\SrtTrail.txt.

Using a Windows 7 recovery environment

If the main Windows 7 installation won’t boot, you can load a recovery environment from your installation media or the hard drive. This boots a simplified version of Windows to diagnose and fix problems.

To load the recovery environment:

1. Insert installation media or boot from recovery partition

If you created a recovery partition, choose it from the boot menu. Otherwise use your DVD or USB drive.

2. Choose “Repair your computer”

3. Select “Windows 7 Recovery Environment”

From here you can access the Command Prompt, System Restore, Startup Repair and other recovery tools to identify and repair hard drive errors.

Replacing damaged hard drive hardware

If your hard drive has physical damage and chkdsk or SFC scans report unfixable errors, the disk may need to be replaced. Here’s an overview of that process:

1. Backup important data

Before replacing the damaged hard drive, be sure to copy any important files or folders to separate storage media.

2. Install the new hard drive

Power down, swap out the old drive for a new one, then boot back up.

3. Partition and format new drive

Use Disk Management in Windows to create partitions on the new drive and format them. Assign drive letters.

4. Clean install Windows 7

With the partitions prepared, boot from your Windows 7 DVD or USB and perform a fresh installation.

5. Restore data

Once Windows is installed, restore your files and settings from backups. Reinstall any applications needed.

With a new, healthy hard drive installed Windows 7 should boot and run properly again.


Troubleshooting and repairing hard drive errors in Windows 7 begins with using utilities like chkdsk and SFC to detect and fix file system and system file corruption. Bootrec can rebuild damaged boot configurations. For more serious startup issues, Startup Repair or a Windows 7 recovery environment contain additional diagnostic and repair tools. If the hard drive has physical damage, replacement may be required. Backing up important data beforehand makes the transition easier. With the right methods, most hard drive problems on Windows 7 can be resolved and your system restored to smooth operation.