If you've had your computer for a while and it's starting to act slow and sluggish, chances are that it's time to defragment your hard drive. What happens is that the files become disorganised, literally "fragmented", and that's why they take so long to open. This fragmentation is normal - to a point. Beyond that point, it becomes a real problem, and can slow down even a fast modern computer.
Defragmenting your hard drive is quite easy, and should be done regularly. This is DIY computer support.
The basics. Defragmenting from the beginning:
On your computers start menu:
1. Click on Start > Programs > Accessories
2. Click on System Tools and then on Disk Defragmenter. Windows built-in disk defragmenter program will open.
3. The computer will need to assess the drive before defragmenting. Left click once on the hard disk click Analyse.
4. If appropriate, the dialog box will say "you should defragment this volume". Click Defragment to start the process. If not, you can close and exit the program.
Windows Vista and 7 (You may need an administrator's password)
1. Click on the Start Button > All Programs > Accessories
2. Click on System Tools and then on Disk Defragmenter. The Windows Disk Defragmenter will open.
3. Select the disk you want to defrag (typically this will be C drive)
4. Click Analyze Disk to check the amount of fragmentation on the disk
5. Click Defragment Disk to start defragmenting
Defragmenting isn't necessarily quick. On average, it takes between 30 minutes and an hour. (If you've had the computer for a few years, and have never defragmented before, it may take a little longer.)