Anilrgowda

There are several reasons that a Windows computer 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 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 your computer is still running slowly, 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. For more information, see the Knowledge Base document How do I install or uninstall components of Windows 95, 98, or Me?
Note: The Windows XP default desktop view and Start menu are different from the Windows Classic View (e.g., in Windows 2000). Therefore, navigating to certain items can be different. In the interest of broad applicability, most Knowledge Base instructions assume you are using Classic View. For information about switching your Windows XP default view to Classic View, see In Windows XP, how do I switch to the Windows Classic View, Classic theme, or Classic Control Panel?
Insufficient RAM

UITS recommends the following minimum amounts of RAM, depending on your operating system:

Windows XP	256MB
Windows 2000	64MB
Windows NT Workstation (3.51 and 4.0)	32MB
Windows Me	64MB
Windows 98	32MB
Windows 95	16MB
Windows 3.1	8MB

These limits are much higher than those suggested by Microsoft, but are more realistic.
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. But in a few cases, the computer will function, but badly. In this case, the fix is to identify the incompatible or defective RAM and replace it. The best thing to do is to identify the proper amount 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

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 ScanDisk 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:

1. Double-click My Computer.
2. Right-click the icon for the drive you want to defragment (usually (C), and then select Properties.
3. Click the Tools tab.
4. In the "Error-checking" section, click the Check Now... button.
5. Check the Automatically fix file system errors and the Scan for and attempt recovery of bad sectors boxes, and then click Start.
6. A dialog box will appear, 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, and then restart the computer.

To run ScanDisk from Windows 95, 98, or Me:

1. Click the Start button and select Programs, and then Accessories.
2. Click System Tools, and then click ScanDisk.

Fragmented hard drive

A fragmented hard drive will make the computer hunt around the hard drive 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 Virtual Memory 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:

1. Click the Start button and select Programs, and then Accessories.
2. Click System Tools, and 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.
Note: For security and support reasons, UITS recommends using Windows 2000 Professional or Windows XP Professional, rather than NT Workstation 4.0, on Indiana University's network. Microsoft retired both mainstream and extended support for this version in June 2004, which means security updates are no longer being developed. For more information, see Microsoft's Windows Desktop Product Lifecycle Guidelines page at:
http://support.microsoft.com/?LN=en-us&pr=lifecycle