After reading through number of posts here and not finding anywhere step by step instructions on how to proceed with multibooting I experimented myself and after a few trials now it appears that I have succeeded. Someone here suggested to go with an initial first 100MB partition under C, and then from the rest of the HDD create logical partitions for booting OS's. It appeared quite sound but I couldn't find the details as how to exactly go with this. Boot files are automatically installed there and if successfully hidden from each other both OS,s should be assigned the same letter. In this way the files of two identical OS's don't get mixed. I proceeded with activation of OS Selector from a bootable disk and it installed itself to the C partition. I already had XP installed and I wanted to install another one for working with music only. I previously partitioned my HDD into four partitions. I came into difficulties when OS Selector would apparently hide the existing XP but when the choices were presented while installing another XP as to which partition to boot it was obvious that the system wasn't hidden. Installing and reinstalling number of times I was learning as I went on. By disabling the OS Selector and hiding the system from within Disk Director I managed to truly hide the installation of the new system and gain the same position for both OS's under the same letter, invisible to each other. In this case they both had letter D. At least I thought so and actually the newly installed XP didn't see the first one, but when I went back to the first XP it was still able to see the newly installed XP. Then I disabled the OS Selector (since although it was saying that the system was hidden obviously it couldn't hide it properly for some reason) and used Disc Director to hide the system. It appears that OS Selector overrides the commands of the Disk Director and the only way to actualise the command of DD is to temporarily disable OSS. It worked fine this time but when I tried to go back to the first XP I couldn't log on into the system. To overcome that I repaired the OS Selector via bootable disk and managed to log on fine. Now both systems are under the same letter (D), independent of each other and the boot files are stored on the first partition (C). Everything seems to work fine apart from one thing. The letter E is missing on both XP's. The orther of the letters is C, D, F, G. Not sure if that is normal. As many others mentioned here there aren't exact instructions on how this should be done or if there are I couldn't find them by searching through google and the forums. Wander if anyone had suggestions that would simplify this procedure in the future and if I could have achieved this an easier rote.