   Multi-Booting
  Hello again, haha :).Recently I decided that I wanted two OSs on my computer... Windows XP on partition A(which I have now) and Windows Vista on partition B. So what I did was get "Norton ParitionMagic 8.0" as it seems to be the best when it comes to partitions and then split my hard drive into two paritions. The question would be... what should I do next in order to install Vista?I mean I tried some experiments which didn't work at all. For example when I made the second partition I restarted my computer and then loaded the Windows XP installation CD. I then went on to the part of the installation which allows you to select the partition that you want to install Windows XP on, for some reason only one partition showed up... the partition which already had XP on it, the other one wasn't there at all. I still need to get my Windows Vista installation CD which is why I didn't use one for the "experiment".If you guys have any ideas please mention them.Thanks guys,Fissure.   
  In order to install multiple Windows instances on one machine, you need to run the installers in correct order; from earliest to latest version. This is necessary because of two major reasons: 1: Earlier Windows installers cannot recognize newer installed operating systems' footprint on the disk as the newer system's footprint didn't exist during making of the earlier installer.2: The older OS loader doesn't know how to boot the newer systems, as is the case between XP and Vista, where the boot system was changed. Vista boot loader will run XP just fine, but you need to install XP first, and Vista after that.You are correct in reserving a separate partition for each OS instance - this avoids conflicts between the systems very cleanly. It is also technically possible to install XP and Vista to a same partition (I've done this as a test), but it requires a bit of hacking against the install image, and the system directories' names are seriously messed up on such instance of Vista due to it avoiding duplicating names of existing directories.I have never trusted the so called "partition magic" systems because they do create odd problems occasionally. I always prefer to work with a clean system and define the partitions properly upon installation of the (first instance of) operating system. Of course, take backups of your data before you do this on an existing system! Re-partitioning of a hdd with the tools supplied by Windows installer will effectively cause you to lose the data on the drive.   ;  Thanks for your post mate, quite informative :). So I'm guessing I'm on the right lines judging by your post. I've installed XP(first) and have two separate partitions. The next step would be to install Vista right? Would the installer be able to pick-up the second partition or are there tasks that must be performed?When you say "Of course, take backups of your data before you do this on an existing system! Re-partitioning of a hdd with the tools supplied by Windows installer will effectively cause you to lose the data on the drive." what do you mean precisely? Am I under a risk of losing data? If so please state how.Thank you,Fissure.;  It is always best to take backups before messing with partitions, and at regular intervals (such as every week, for example) in any case.If you now have two functioning partitions with your data intact, you are past the point of immediate danger of losing said data. However, Windows installer has tools that can do partitioning as well as formatting of drives, so you need to be careful during the initial configuration in order to not erase your data.Partitioning a drive by using conventional methods involves writing a new partition index to an area of the drive hardware reserved for that purpose. This means that the previous file indices as well as file systems become invalid. The resulting effect of this is somewhat like "quick format" in which the file contents do not get erased physically, but their physical space gets marked as free space and you lose the file addresses - that is, you cannot trivially access the files anymore unless using special tools that do not depend on the file system being intact. Formatting - by itself - is a separate operation that establishes a file system to a partition and optionally erases all data that was previously in the physical space corresponding to that partition.Partition Magic works by modifying the disk's partition index directly and moving appropriate file system entries around. This is always risky because if even a small thing goes wrong, files or entire file systems may be permanently lost even though the physical disk would function just fine. Therefore, my experience has shown that the best practice is to partition disks before they contain any data - because there is no risk of losing anything by then.   ;  I'm sorry dude I can't seem to figure out what you're trying to tell me. Basically are you trying to tell me to make a back-up copy of my Windows XP? and then to install Windows Vista but make sure that I don't make any mistakes?Thanks again,Fissure.   ;  Backing up your data regularly prevents loss of said data. You have to decide for yourself whether your data is worth protecting. That said, I would have taken a backup just before running Partition Magic, but it's too late for you to catch that train now. The all-encompassing point is that you should take backups regularly if you value your data at all, even if you don't anticipate imminent system failure.   