There are several reasons that a PC might be running slowly. If you usually leave your computer on and don’t restart it very often, you may see a significant slowdown in PC performance, and perhaps “out of memory” error messages. When you leave the computer on and don’t restart it through the Shut Down… option on the Start menu, it causes the Random Access Memory (RAM) to become full, which doesn’t leave as much space for applications to function freely. Simply restarting your computer should flush the RAM and speed up the computer.
If you are still seeing a slowdown in computer performance, you may need to free some space on the hard drive by removing unneeded programs. You can do this by clicking Start and selecting Settings and then Control Panel. Select the Add/Remove Programs option.
Note: In Windows XP, the default desktop view and are quite different than they are in the Windows Classic View. Therefore, navigating to certain items may be different in XP; for example, the path from the Start menu to the Control Panel in the default XP view is simply Start, then Control Panel, whereas in the Classic View it is Start, then Settings, then Control Panel. In the interest of broad applicability, most instructions in the Knowledge Base assume that you are using the Classic View. There are several steps you can take to switch from the Windows XP default view to the Windows Classic View.
Insufficient RAM
Windows XP 256MB
Windows 2000 At least 64MB
Windows NT Workstation (3.51 and 4.0) At least 32MB
Windows Me At least 64MB
Windows 98 At least 32MB
Windows 95 At least 16MB
Windows 3.1 At least 8MB
These limits are much higher than those suggested by Microsoft, but are more realistic.
Defective or incompatible RAM
In a large majority of cases, a computer with either defective or incompatible RAM will simply not function. Other times, it will give clear and unambiguous blue screen errors. But in a small minority of cases, the computer will function badly but will still function. The fix in this case is to identify the incompatible or defective RAM and replace it. The best thing to do is to identify beyond any doubt what the proper RAM should be 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
There may be errors on your disk, such as file allocation errors. These errors can cause error messages as well as slow performance. You can run from DOS 6.0, 6.2, or 6.22 or from Windows 95, 98, Me, NT, 2000, or XP to fix these errors.
Note: Be sure to run ScanDisk before you run DEFRAG or the Disk Defragmenter. ScanDisk will mark all the bad sectors on the disk; if you run DEFRAG or the Disk Defragmenter before ScanDisk, it might move good information into a bad sector, causing the information to be lost.
To run ScanDisk from Windows NT, 2000, or XP:
Double-click My Computer.
Right-click the icon for the drive you want to defragment (usually (C:)), then select Properties.
Click the Tools tab.
In the “Error-checking” section, click the Check Now… button.
Check the Automatically fix file system errors and the Scan for and attempt recovery of bad sectors boxes, then click Start.
You will get a dialog box saying: “The disk check could not be performed because exclusive access to the drive could not be obtained. Do you want to schedule this disk check to occur the next time you restart the computer?” Do not worry; this is expected behavior. The C: drive is busy because Windows is running, and in Windows NT, 2000, and XP, the scan runs best before Windows loads. Simply click Yes to schedule the scan, then restart the computer.
To run ScanDisk from Windows 95, 98, or Me:
Click the Start button and select Programs, then Accessories.
Click System Tools, then click ScanDisk.
Fragmented hard drive
A fragmented hard drive will make the computer hunt around the hard drive in order to find pieces of files. You can fix this by using a defragmenter. If you use Windows 95 or 98, you might try turning off before running the defragmenter (make sure you turn it back on afterwards, though). You can run the defragmenter from DOS by using the DEFRAG command.
To run Disk Defragmenter in Windows 95, 98, Me, NT, 2000, and XP, follow these steps:
Click the Start button and select Programs, then Accessories.
Click System Tools, then click Disk Defragmenter.
Note: Windows NT 4.0 does not have a defragmenter built in. You will need to locate a third-party disk defragmenter; some are available for download from the Internet.
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, so it’s running slowly but it is running. The cure for this is to either clean out 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.