Over time and use with a windows machine you may notice that it does not run as fast as when you first got it.
This is usually because of a number of different problems that can occur with regular use of a computer. The smart computer user knows about these things and how to repair them on their own rather then having to hire a technician to solve the problem, (costing you time with out your computer and usually around 50 dollars an hour).
Possible problems usually include one or many of the following things:
Viruses
They happen, even if you spend all the money you can on antivirus software, you likely don’t even know you have one.
Spam
Loosely falls under the same definition as a virus but with some negligible variations, can also include programs that hit you computer with nasty pop ups and redirect you to web pages you don’t want to visit.
Registry
This is a comprehensive list of all programs that have ever been installed on your computer, sometimes when you uninstall a program some information can still be left on this list, the longer you have your computer the larger this list is likely to be.
To much junk
Unused programs and applications (different browser menus, and other programs)
Start up programs