How to Reinstall an Operating System
This question often gets asked and it is as much of a mystery to some as it is easy to others. So why should you even consider it?
Let's say you get infected with spyware or viruses, you will NEVER rid yourself completely of the threat those files once had, especially spyware. It's been a couple of years and your system is getting slower and sloooower or you just want to tinker and explore some new possibilities, my personal favorite, which is also a great learning tool.
I could tell you volumes on how to do it but much of it would be a duplication of the same information I was exposed to years ago so I will point you to those sites but I believe it is better for now to explain some basics.
Your hard drive is a delicate item and arguably the most important in the system. Think of the hard drive as a large dinner plate that you can divide into partitions or concentric rings. Each of these rings, or partitions, can perform different functions.
The inner most ring, your C Drive (referred to as the root drive) should your operating system and installed programs. The next outer ring, or partition, can be configured to hold your data, and if desired a third partition (enough of the ring analogy) can be used for special items or project data. So why all the bother. Well, if your operating system crashes due to anything other than physical damage, the other partitions are still intact and most importantly so is your data. Reason enough to partition your hard drive. The next reason is that most new systems are coming with very large hard drives and the larger the root partition (C Drive) the more fragmented the drive will become. A fragmented drive runs slower and takes longer to defrag.
Here are some very good links on the "how to" part: