ARCHIVED: Why is my Windows computer running slowly?

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If your Windows computer is running slowly, following are possible causes and solutions.

On this page:

Unneeded programs
Programs loading on startup
Malware
Windows updates
Insufficient RAM
Defective or incompatible RAM
Hard disk errors
Fragmented hard drive
Overheating CPU

Unneeded programs

You may need to free some space on the hard drive by removing unneeded programs; see ARCHIVED: In Windows, how do I uninstall programs?

Programs loading on startup

Configure programs to automatically load on startup only if you really need them, since some programs load into your notification area, and can cause your computer to slow down. You can typically change startup options in the program preferences, but you may need to check the help documentation. Even if programs do not load automatically, you can still access them via Start, and then All Programs, or via an icon on your desktop. For more, see Prevent programs from starting automatically in Windows

Malware

If you are experiencing a significant number of unwanted pop-up windows, your computer most likely has some type of spyware or malware infection; see ARCHIVED: What is spyware or adware, and how can I remove it?

Windows updates

You may have pending Windows updates that need to be installed. Keeping Windows up to date helps maintain the security and reliability of your operating system, which helps it run at optimal speeds. See ARCHIVED: For Windows, how can I get software updates and patches?

Insufficient RAM

Your computer may run slowly if it does not have sufficient RAM. For minimum hardware requirements for your operating system, see:

Defective or incompatible RAM

In most cases, a computer with either defective or incompatible RAM will simply not function. Other times, it will give clear and unambiguous blue-screen errors. In a few cases, the computer will function, but badly. The solution is to identify the incompatible or defective RAM and replace it. It's best to identify the proper amount of RAM for your computer and use only that, and, when problems occur, to run burn-in tests (some are available for free download) to ensure the RAM is still physically good.

Hard disk errors

Your disk may contain errors (e.g., file allocation errors), which can cause error messages as well as slow performance. To fix these errors, run ScanDisk.

For help, see Microsoft Support.

Fragmented hard drive

A fragmented hard drive will make the computer search the hard drive to find pieces of files. You can fix this by defragmenting your hard drive.

For help, see Microsoft Support.

Overheating CPU

Every Pentium-class and newer computer has fans and heat sinks specifically for cooling the CPU. When the fan wears out or becomes clogged with dust or other debris, the temperature of the CPU rises. In most cases, the computer simply stops operating, but sometimes the entire computer will appear to be running slowly or taking long pauses. To rectify this, clean the CPU fan so it spins at the proper rate, clean out the heat sink so it dissipates heat properly, or replace the fan/heat sink unit.