One of the common reasons for slowing down of computers is problems in the registry. If you get frequent error messages and/or the computer goes in to frequent freezes, that may be an indication that your computer needs a cleaning of it's registry. This can be done with a good registry fixer.
Every time you install a new program or uninstall an old program, windows registry changes and files become disorganized. There are many registry fixers available, but which one does a proper job cleaning your computer?