I am running Scientific Linux 4.3 and I want to upgrade to the latest version 5.4. Now, I have downloaded the two .iso files. If I install these, will I be able to keep my existing file system, or will the volume in my hard drive be erased, and hence I will have to save my programs and files somewhere else. In addition, what else can go wrong when doing this? (I will not have a problem with insufficient disk space. Thank You for Responding: Andrew Stallard