Yesterday, I’ve received an email from Hafnim who is currently having trouble of Windows System CPU usage continues to peek or stays at 100% and asked me for a solution.

I’ve did some research and and it seems like this problem is frequently happened. This issue can be caused by a few possibilities below.
1. Lack of sufficient memory.
2. Hard drive failure.
3. Heavy programs being run in the background.
4. Infections of spywares, worms, trojans, viruses or any other malwares.
5. Slow hardware that cannot sustain heavy applications.




Below are the solutions according to the above described causes:

1. Lack of sufficient memory
Make sure you have more than 20% free space in your hard drive where your operating system is stored. If not, delete some unsed files until you have more than 20% free space in your primary hard drive. You can consider buying a new and better hard drive if you need more storage space.


2. Hard drive failure
Check if your hard drive is failing. Defragment your hard disk to determine how many bad sectors you have in your hard drive. A bad sector cannot be repaired, but it can be marked as unusable. You can also consider buying a new hard drive if you are having bad sectors on your current hard drive.


3. Heavy programs being run in the background
To disable heavy programs that are running behind your windows, you must first determine each process that is running in Windows and the CPU usage it is using. To do so, open the “Windows Task Manager” by pressing CTRL+ALT+DEL buttons, be sure you hold each of the buttons while you pressing them, and then click the “Processes” tab. The list show you the programs that are running in your windows. Click the CPU button above the list of programs twice to organize the programs CPU usage from highest to lowest. Now you can see which programs are taking most of your CPU cycles.

You can disable them only if you know what they are. Usually the “System Idle Process” will be using most of your CPU cycles, but it’s perfectly normal, you don’t have disable it. However, if you’re not familiar with what the processes are, you should do a search for those processes to make sure whether they can be disabled or not. To disable any of the processes, simple click on the process and click on the “End Process” button.

The processes that you’ve End Tasked will return each time you start your computer, you will need to disable these programs from running each time your Windows loads. Read How To Disable Startup Programs In Windows XP and Vista?


4. Infections of spywares, worms, trojans, viruses or any other malwares
Computer Viruses, Trojans, Worms, Spywares are designed to corrupt or delete data on your computer and also replicate itself to maximize the infection to other computers. Some of them are also designed to utilize your system resources and use up most of your CPU cycles.

To get rid of these viruses and malicious programs, make sure you have an anti-virus or anti-spyware program installed and running on your computer, scan your computer regularly and delete all detected viruses or malwares. Please also make sure your virus scanner is up-to-date with the latest virus definitions. For additional information about viruses, please read also What Is A Computer Virus? An Introduction To Computer Viruses and How To Avoid Virus Infections.

5. Slow hardware that cannot sustain heavy applications.
This is the most common cause of the problem “CPU Usage 100%”. If the hardware of your computer cannot support the program you’re running, it might use up all the CPU cycles and you’ll notice an obvious decrease in speed of your computer. If you are sure that the above solutions don’t work for you, you might have to try upgrading any specific part to speed up your computer so that it can sustain more heavy applications. If you wish to purchase a newer and better hard drive, please read also How to buy a hard drive.