How to Fix 100 Percent CPU Usage
A computer should never use 100 percent of its CPU capacity. If it does, it is overloaded with information and may have difficulty running efficiently. Programs will stall and run slowly, if at all, and the computer will be in danger of burning out the components quickly. If your computer is running at 100 percent CPU usage, you should shut down some of the processes that are running.
Move your cursor down to the taskbar located at the bottom of your screen and right-click anywhere on it.
Click on "Task Manager" and a dialog box will pop up.
Click on "Performance" at the top of the menu. The two graphs that pop up will show you the current CPU usage. The numbers will change every second, but for the most efficiency, they should be below 50 percent.
Hit the "Applications" tab, which shows you which programs you currently have open. You can right-click on each item and choose "End Task" to free up CPU usage.
Go to the "Processes" tab at the top to see which programs are currently running in the background. If you recognize one or two that have the highest numbers, you can right click on them and choose "End Task" to temporarily stop them and lower the CPU usage, but only if you're sure that the program isn't essential for your computer to run properly.
Go to "Start," "Programs" and "Startup." Choose the programs that you want to disable at startup by right-clicking them and deleting them. Doing this will lower your CPU usage and speed up your computer.
Using an Anti-virus Program
Download an anti-virus software program and install it. Sometimes viruses can cause the CPU to run at 100%, which makes your other programs stall and crash.
Download any updates for the anti-virus software.
Run the anti-virus program and delete any viruses that pop up. Restart your computer when the program is finished running.