This page provides suggestions on what to do if your computer often freezes or stops altogether. An easy way to determine if your computer is in this situation is by pressing the Num Lock key on the keyboard and see the Num Lock LED to see if it turns off and on.

If you can turn on the lights, turn on Ctrl + Alt + Del and End Task programs freeze. If not, proceed through each section in order.

Problems related to software

Software related problems usually cause a computer lock or freeze. If you have a problem with your computer open to a particular program, make sure you have all the latest updates for all running programs. You can find the latest updates for your software through a software developer or publisher.

Tip: If the computer has any malware, viruses, or other malware, it can also cause many problems. Make sure your computer is clean.

Too many programs open

Every program or window you open on your computer takes some computing resources to keep it active. If you have too many programs open simultaneously, your computer may run out of resources, resulting in freezes. Try running only one program to make sure that your freezing isn’t caused by multiple programs running simultaneously.

Driver problem

Outdated or corrupt drivers can also cause a computer lock. For example, if something goes wrong with your video adapter drivers, your computer might lock while playing a game or watching a movie.

First, make sure no errors exist in the Windows Device Manager by opening Device Manager and verifying no “Other Devices” listed. You will also want to check the device list to see if they have a yellow exclamation mark or a red X next to them. If so, you’ll want to visit our page on identifying the problems in Windows Device Manager.

Next, make sure you have the latest drivers for all major devices in your computer (video, audio, modem, and network)—a list of Driver related pages.

Heat-related problem

If the computer processor is getting too hot, it may cause the computer to freeze. If you have recently heard any unusual noises from your computer, such as a high squeak, it could be a sign of a failed fan.

You can start by verifying that the failed fans on the power supply are working by checking the computer’s back and seeing if the failed fans are moving and moving smoothly. For other fans on the computer, you have several options. You can open the computer and do a physical check, or if the computer monitors the fans RPM, enter the CMOS settings and make sure the BIOS doesn’t report any errors.

Note: Laptop users may also want to try turning the laptop on a book or notepad so that the air can reach the bottom of the laptop to help verify if the laptop has a heat issue.

Users can also determine how hot the computer is using the onboard heat sensors. If your computer is equipped with these sensors, make sure your CPU doesn’t overheat.

Hardware problem

Note: Some of the steps below require you to turn on your computer. While working inside the computer, pay attention to ESD.

Faulty hardware or configuration problems can cause the computer to be locked. If you recently added any new hardware to the computer, temporarily remove it to ensure it’s not the cause of the problem.

Before trying to remove any hardware, make sure the computer has no conflict in Device Manager.

If you haven’t installed any new hardware, the next best solution is to remove the parts one by one. For example, you can withdraw your modem, network card, sound card, or any other expansion card as they are not needed for the computer to function. Start the computer without these tags to see if they are the cause of your problem. You should also try unplugging any of the peripherals (plugging in) once to see if they’re causing your problem.

The serious problem with Windows

If you’ve tried all of the above and your computer continues to lock frequently, Windows may be corrupted. Try running through the basic troubleshooting steps for your version of Windows. If these additional steps do not resolve your issue, we recommend that you back up all your valuable information and then delete and reinstall Windows.

Hardware error

If your computer turns off abnormally during or after installing your operating system, the hardware components inside your computer may be damaged. If so, the faulty hardware could be RAM, CPU, Motherboard, or Power (in that order).

If you access parts from another computer known to be working, try swapping out parts to isolate faulty hardware. If not, you will need a computer.