There are a number of things that can cause your PC to become unresponsive or to freeze altogether. Fortunately, while it’s very frustrating, it’s rarely a serious problem and there are lots of things you can do to get it running smoothly again.

Why do computers freeze?

There are a number of reasons your PC might become unresponsive. It could be hardware or software, or a combination of both. One common reason is that it’s overheating. This is a common cause of laptops freezing. When you’ve been using it for a while, particularly if you’ve been running demanding tasks like playing games or watching HD video streams, the CPU will get very hot and the fans will struggle to keep it cool. In these circumstances, the operating system slows your PC down in order to prevent damage from overheating.

Another common cause is running out of free memory. This can be caused by having lots of applications running at once, or by an application malfunctioning and hogging RAM, or even by malware running in the background. Talking of malware, it’s another potential cause of freezes, outside of hogging RAM.

Fortunately, there are several steps you can take to track down the cause of an unresponsive computer and fix it.

How to fix an unresponsive computer

If you think overheating might be the problem — if the fans are spinning loudly and your laptop feels hot to touch, it’s likely that it is — start by quitting all applications you’re not using currently. Wait a little while and see if the fans spin down and your PC cools down. If that doesn’t work, quit all applications, saving your work first, and then reboot your PC.

If it’s still running slowly when you reboot, or if it starts running slowly shortly afterwards, you may need to take action to clear vents of any dust that might have built up. Take a look at the vents, using a torch and check if they look blocked. If they do, you should clear them. You can use a can of compressed air to do that, but be careful with it – you don’t want to blow the dust into your laptop. Do some research on the best way to clear fan ducts and vents before you start.

How to identify and quit an unresponsive application

If your PC’s fans aren’t spinning and it’s not overheating, the most likely cause of the freezing is an application that’s misbehaving. The first step is to find out which application is the culprit. And you do that using Task Manager.

  1. Press Control+Shift+Escape to launch Task Manager
  2. Choose More Details
  3. Click on the CPU column
  4. If you see an application that’s occupying close to 100% of CPU cycles, click on it and select End Task to quit it
  5. If there are no clues from CPU cycles as to which application is causing problems, click the RAM column to order processes by the RAM they’re using
  6. If there’s an application that’s using much more than a reasonable share of available RAM, click on it and press End Task

Sometimes it’s not an application that’s causing your PC to freeze but a process running in the background. Those will also show up in Task Manager. If you identify one of those is at fault, you can end it in the same way, by pressing End Task. However, if you don’t know what the process is, you should Google its name first to check it’s not critical.

If Task Manager doesn’t provide any clues, try the Windows Diagnostic Memory Tool. Click on Start and search for “memory”. Run the tool and see if it finds anything — it will reboot your computer as part of the process.

Prevent applications running on start-up

Autorunning applications are a common cause of PCs running slowly. They increase the time it takes to boot, then run in the background, occupying resources. Some applications, like antivirus tools need to launch on startup so they can scan your computer for malware. Others, like helpers for Spotify or iTunes don’t and can safely be disabled.

There are a couple of ways you can prevent programs launching a start up. Here’s the manual method.

  1. In Task Manager, choose the Startup tab
  2. Locate the programs you want to stop loading at startup
  3. Right-click on the first program and choose Disable
  4. Repeat for each one  you want to prevent running at startup
  5. Close Task Manager

If you have lots of startup programs, that could take a while. An easier way to prevent applications from launching when your PC boots is to use the Autorun tool in CleanMy® PC.

  1. Download CleanMy® PC and install it
  2. Launch it once it’s finished installing
  3. Click on the Autorun tool in the left hand sidebar
  4. You’ll see a list of programs that run automatically when your PC starts
  5. Toggle the switch next to the apps you want to prevent from autorunning to the off position

Disable Fast Startup

Fast Startup stores a snapshot of your current status in a Hibernation file so that when you select Hibernation mode, your PC goes back to where you were quickly. However, creating that snapshot uses resources and some users have reported problems with it, so you can disable it.

Again, this is something you can do in CleanMy® PC quickly and easily. However, if you want to do it manually, here’s how:

  1. Click Start
  2. Select “Choose what the Power buttons do”
  3. Click “Change settings that are currently unavailable”
  4. Type in an administrator username and password, if necessary
  5. Uncheck “Turn on fast startup (recommended)”
  6. Choose Save changes

Dealing with a PC that freezes or becomes unresponsive frequently is frustrating. However, if you take the steps above and resolve the issues that are causing it to freeze, your computer should be running smoothly again in no time.