Clean up disk errors
Run once a week
Whenever a program crashes or you experience a power outage, your computer may create errors on its hard disk (sometimes referred to as a hard drive). Over time, the errors can result in a slow PC. Fortunately, the Windows operating system includes several PC tools, including a Check Disk program, to identify and clean any errors on your computer and to help keep it running smoothly.
Note: You must be logged on as an administrator to perform these steps. If you aren't logged on as an administrator, you can only change settings that apply to your user account.
Run Check Disk:
Windows 7 and Windows Vista users
1. Click the Start button 
, and then click Computer.
, and then click Computer.2. Right-click the hard disk drive that you want to check, and then clickProperties.
3. Click the Tools tab, and then, under Error-checking, click Check now.
o To automatically repair problems with files and folders that the scan detects, select Automatically fix file system errors. Otherwise, the disk check will simply report problems but not fix them.
o To perform a thorough disk check, select Scan for and attempt recovery of bad sectors. This scan attempts to find and repair physical errors on the hard disk itself, and it can take much longer to complete.
o To check for both file errors and physical errors, select bothAutomatically fix file system errors and Scan for and attempt recovery of bad sectors.
4. Click Start.
Depending upon the size of your hard disk, this may take several minutes. For best results, don't use your computer for any other tasks while it's checking for errors.
Note: If you select Automatically fix file system errors for a disk that is in use, you'll be prompted to reschedule the disk check for the next time you restart your computer.
Windows XP users
Remove temporary files
Run once a week
Your computer can pick up and store temporary files when you're looking at webpages and even when you're working on files in programs, such as Microsoft Word. Over time, these files slow your computer's performance. You can use the Windows Disk Cleanup tool to rid your computer of these unneeded files and to help your PC run faster.
Run Disk Cleanup:
Windows 7 users
Windows Vista users
Windows XP users
Optimize your data
Run once a week
As you add programs and files to your computer, it often breaks files side by side to increase the speed of access and retrieval. However, as files are updated, your computer saves these updates on the largest space available on the hard drive, often found far away from the other adjacent sectors of the file.
The result is a fragmented file. Fragmented files cause slower performance because your computer must now search for all of the file's parts. In other words, your computer knows where all the pieces are, but putting them back together in the correct order—when you need them—can slow your computer down.
Windows includes a Disk Defragmenter program to piece all your files back together again and to make them available to open more quickly.
Note: Windows 7 and Windows Vista are preconfigured to run Disk Defragmenter on a weekly basis. If you would like to run the tool manually or to adjust the schedule, click the section for your specific operating system.