If you are currently using Windows XP (and most people still are), the upgrade to Windows 7 (which is highly recommended) is problematic.
First, you have to back up everything you want to save, including some things which are hard or cumbersome;
Second, you have to make sure you still have copies of all of your programs;
Third, you must format the hard drive;
And then, you can install Windows 7.
Now there is an easier way. Cnet has an article on a new product soon to be released which will make the process much easier. (Click here to read the article.)