If your computer is slow, you may have an outdated operating system
No piece of software is ever considered 100% “complete”. If a piece of software was to be complete it would be bug free, perform flawlessly and be unaffected by future developments in technology. The first two features are theoretically possible but no software completely escape the future developments of technology.
Luckily, operating systems these days come with built in update systems that allow companies like Microsoft to push updates to computers on a mass scale via the internet providing bug fixes, additional features and most importantly performanc enhancements.
Many people however don’t think about updating their system, and although Windows XP and Windows Vista come with automatic updating capabilities they aren’t always enabled by default. Whilst not updating your operating system may not have a huge effect on the operating system itself, more than likely other applications you use will perform better when dealing with a more stable foundation.