If all you want is to re-adjust the size of the partitions, the easiest way to do this is by downloading and installing Easeus Partition Manager 1.6; this program is free for personal use, and is by far the most simple and intuitive partition manager I have ever come across. You should run it from within Windows; you can use it to create a boot CD, but if you run it from the CD, it will wipe your partions (if I'm not mistaken). It is a very safe and reliable program and you will not lose your data.