Fixing 0xc000021a stop (blue screen) errors in Windows 7

If you can start Windows 7

Making use of System Restore to Undo Recent Changes

One of the easiest move to make first is getting the system restored. This will get recent changes happening in your computer system undone including the files that could be the root cause of the problem. System recovery does not affect your personal files such as emails, documents or pictures.

System Restore: How you can Open It

1. Click on the Start button. In the System Restore search box, enter System Restore. Enter the administrator password if necessary.


Making use of Action Center to troubleshoot issues

A user gets a report from Windows when there is an occurrence of problem concerning hardware or software. Action Center can be handy in terms of checking an answer to an issue.

Looking for Solutions

1. The initial step to opening Action Center is pressing Start, then Control Panel, and followed by pressing ‘Review your computer’s status’ under System and Security.

2. Just click Maintenance.

3. Find Check for solutions to problem reports then click Check for solutions under it. You’ll get a notification from Windows about any possible solutions to the reported troubles.


Check for software updates – Go to Windows Update

Troubles might be resolved through recent updates in Microsoft. Windows Update is your partner when it comes to updating the newest system drivers and updates on your computer system. To make sure that most recent updates would be installed in your Windows 7, manually check Windows Update.

Try To See Any Updates

1. The first move to make is hitting Start. Type Update in the search box then search for Windows Update in the results then click it.

2. Click Check for updates in the left pane to run a search for the latest computer updates.

3. When you are prompted that there are available updates, or you should review updates, you can see and select the updates by clicking on the message.

4. To have more details, navigate and click on update. To install updates, select their respective boxes, then hit OK.

5. Simply click Install updates. Review the license terms, and then hit Finish (if applicable). You may provide a password or confirmation if administrator password or confirmation is asked.


Visit the manufacturer’s website to search for drivers

The problem can also occur because of an incorrectly set up or wrong device driver. Keeping that in mind, see if you have recently installed a sound card or video card.

Make sure you have the newest driver for the device set up. The device manufacturer’s website is an excellent source of updated drivers. Drivers are mostly self-installing, all that you should do is download them and just double click to start the installation.

When the driver does not install itself, these steps should be followed:

Updating a driver

You have to be logged on as an administrator for this procedure.

1. You may begin by hovering the mouse to Start button then click the Device Manager, click the Control Panel, then the System and Security and lastly under the System, you might click on the Device Manager. Provide a verification or a password just in case an administrator password or confirmation is requested.

2. In the listing of hardware categories, find the device that you want to update, and then double-click the device name.

3. Go to the Driver tab where one can click Update Driver. Ensure the instructions are followed. You might need to provide a password or verification if prompted for administrator password or confirmation.


Troubleshoot problems through Safe Mode

Windows in Safe mode has limited features. The functions are limited to files and drivers required to run Windows and those that can help troubleshoot any software problems. For instance, if you can shut down a program that runs once Windows start, running Windows in safe mode and deleting the program might do the trick.

Putting your computer in safe mode

1. Simply click restart after DVD’s and CD’s are removed. Go to the Start button then click the arrow after the Shut Down button and hover the mouse to Reboot and click.

2. Try to perform one of the given below:

• Hit and hold the F8 key when restarting your laptop or computer which has only a single operating system installed. You should press F8 before the Windows logo appears. If you are caught up by the Windows logo, you need to simply wait for the Windows logon prompt so you can restart your computer and try again the first step.

• When there is more than one operating-system in your computer, you must first highlight the operating-system you would like to run in safe mode using the arrow keys, just before pressing F8.

3. Use the arrow to highlight the options you want to run in safe mode then press enter after, you can find this on the Advanced Boot Options screen. For additional information about options, see Advanced startup options (including safe mode).

4. On your pc, just enter a user account that can run as administrator.

When safe mode is activated, the words Safe Mode will show up in your screen’s corners. Exiting safe mode will need your laptop or computer to be restarted and simply let Windows do a normal start-up.


Check if there’s error in hard Disk and memory of your personal computer

The errors on your hard disk or random access memory (RAM) might also be the reason why you are encountering problems in operating your computer.

Windows 7 comes with tools perfect for recognizing and resolving a few errors linked to its hardware. Serious errors may need you to contact the hardware manufacturer for support.

Try to see if there’s any hard disk error

1. Simply click Start button to open your computer and hover the mouse to Computer and press enter.

2. Right-click the drive that you like to check, and then click Properties.

3. Click Tools, and then click on Check Now under Error-checking. Provide the password or confirmation code when you are asked to.

• To automatically repair issues with folders and files that the scan detects, choose Automatically fix file system errors. If you do not choose this option, the disk check won’t fix the problems but will only report them.

• Perform an extensive check by choosing Scan for and attempt recovery of bad sectors. You might need to wait for longer for this scan to complete since it works to find and repair physical problems found on the drive itself.

• To check for both file errors and physical problems, pick both Automatically fix file system errors and Scan for and attempt recovery of bad sectors.

4. Navigate to Start button and then click.

Try checking for memory problems

1. The initial step would be opening the Memory Diagnostic Tool. Go to the Start button, then click the Control Panel button. In the search box, type Memory, and then click Diagnose your computer’s memory problems. If you’re prompted for an administrator password or confirmation, type the password or provide confirmation.

2. You’ve got the option when to run the tool. Restarting your laptop or computer and running the tool immediately, means you should save your tasks and close all programs which are running. Memory Diagnostics Tool also runs instantly after a Windows reboot.