Why is my Windows computer running slowly?

Username:
Password:

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

On this page:

Unneeded programs

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

Programs loading on startup

Configure programs so they do not automatically load on startup. Some programs (e.g., instant messaging programs) load into your system tray, and can cause your computer to slow down. To resolve this, in the program preferences, change the startup options; you may need to check the help documentation. You will still be able to access the programs via Start, and then All Programs, or via an icon on your desktop. For more, see In Windows, how can I prevent a program from starting automatically?

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 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 For Windows, how can I get software updates and patches? and What is Windows Update, and how do I use it to update my Windows installation?

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 fix is to identify the incompatible or defective RAM, and replace it. The best thing to do is to identify the proper amount of RAM for your computer and use only that, and when problems occur, to run burn-in tests (some free ones are available for 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; see In Windows, how can I check a disk for errors?

Fragmented hard drive

A fragmented hard drive will make the computer search the hard drive to find pieces of files. Fix this by using a defragmenter; see In Windows 7, Vista, and XP, how do I defragment my hard drive?

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 ineffective because it's clogged with dust or other debris, the temperature of the CPU rises. In most cases, the computer simply stops operating, but in some cases, the whole computer will appear to be running slowly or taking long pauses. Often this happens because the CPU is repeatedly locking up for a few seconds at a time. Sometimes it happens when the CPU is running just hot enough to affect its performance but not hot enough to lock up. 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.

This is document aenb in domain all.
Last modified on May 03, 2011.