How to Unistall an OS using itself?

You can't uninstall an operating system, you can format the PC or upgrade the OS if possible, but it is impossible to uninstall it. Deleting registry keys that you don't even know what are they used for just shows how you are messing with something you don't understand. Solution for your problem is to fresh install the XP or Vista. That means you have to set the boot device to CD/DVD Rom and then insert the Windows installation CD/DVD, follow the instructions and you'll have fresh installation of Windows in no time. Be aware that you will lose all your data! I also have to add that you can't downgrade from Vista to XP, you can upgrade from XP to Vista, from Vista to Windows 7 (OEM versions are already circulating through the torrent trackers), but there is no way to downgrade... I want to say one more thing. I'm an IT student and I know pretty much about PC's, operating systems, programming, etc., but there is one thing I hate the most and that is when unskilled people claim that Vista is slower than XP, much worse than XP, etc. The problem is that initial release of Vista was like that, but after the SP1 and SP2 Vista is good operating system. I've been also beta testing Windows 7 and I have to say that it is the best operating system Microsoft has ever made. P.S. Don't get me wrong, it wasn't my intention to attack you, but I'm mad when people claim something they have heard and not from their experience... Happy mylotting and take care!

Wow ! Nice to hear all your adventures... just like you, I too like to do such things with my PC ... I guess Vista did not let you install XP because XP is a version of windows that is lower than Vista. If you are installing XP over Vista, you are downgrading your PC. which I guess windows doesn't want you to (now I really don't know why...) XP awesome ??? Never heard of it. Must be some multithreaded OS... I once installed Black XP (I told you i love fooling around with things too !) Ok now about your question. I read on MS's site that if you have 2 or more operating systems installed, you can uninstall one of them by simply booting into the other, going into the directory in which the other windows is installed and deleting the "windows" directory ! So if you wanna uninstall Vista using Vista, then install another Vista and delete the windows directory of the old Vista ! Thats what I can suggest friend ! Take care...

Well friend if you have upgraded Windows Vista on already Windows Xp then you can restore back your Windows Xp. But if you have removed Windows Xp and then installed Vista then you have to install Windows Xp freshly. Please do read the below two articles and in those articles there are procedures to unintall Vista. So, try it.. links are given below:http://www.windowsvista.windowsreinstall.com/uninstall/index.htm If you want to downgrade Vista to Windows Xp please do read the below link:http://www.howtogeek.com/howto/windows-vista/install-windows-xp-on-your-pre-installed-windows-vista-computer All the best...:)

uhm, unless i am mistaken, i think that most new laptops (and desktops) have a recovery system where you can recover the same OS if you want, just like starting with a fresh computer. There are also some computers that are downgradeable to certain operating systems. Like if you purchase a computer with a vista business, it can be downgradeable to XP pro. They have a recovery disc with it or installed in the pC. Lastly, you can uninstall it because normally, computers are sold with the CD of the OS with it, so just restart you computer, and make sure you put the CD in the CD-rom then, boom, it will start the install/uninstall/repair thingy. If you want to re-install it or put another OS, then just put the CD in and reboot. It will start with the blue screen and installing etc. and if you are worried about viruses, try making multiple partitions, and justi nstall your OS in a separate partition, example Drive D. You can allot just a few GB for it, then another partition for your games and another one for important files. Because if you do this, if one drive gets corrupted, you can just format it and not have to remove and reinstall your OS.;) hope this helps.

Hi hora I never dared to use two OS in my PC. cozI hate virus occupying my system and crash it. I don know the process of uninstalling vista using commands from vista itself.

That is impossible...you can not uninstall an os using itself.. Also you cannot use some serious commands like "format" in the drive which the OS is installed.. Try executing format command in windows in the C drive.

well i dont think so you can do that

I have a suggestion for your future forays into OS annihilation, especially if you want to install a previous version of Windows. Deleting the registry will not work, because a Windows installer will look for certain folders or programs to convince itself that it is safe to install a new OS. The main problem is different Windows has a different 'mark'. The easiest thing to do would be to rename the folder or files. Honestly I do not know how it works with Vista or 7. In the previous versions it was the System folder, or System32, or Desktop. This was the technique I used to reinstall the same Windows over itself, without losing any previous setting. I know I am not actually answering your question, but since you have become fearless, I thought the tip or info may become useful in your future adventures in computer maintenance.

Hi Hora... thanks for sharing.. I think, your computer must have a new OS, before uninstall the old OS.

I have no idea how to uninstall an OS using itself? Or maybe it is just like another software that has uninstallation option to uninstall itself. I have never tried to uninstall an OS. What I saw in your post is that XP and Vista are Microsoft softwares that could be operated in one OS, is that right?

gosh hora! u really had joy ride hann!! @ topic, u can dual boot ur OS, for that , u need first install older version of the OS (XP) later once installed XP, u can install Vista or 7, by choosing a fresh installation on another drive. Make sure not to use OS which have been modified. Like windows longhorn, xp music edition or hell edition , these comes filled wid viruses and spywares. Im using a Virtual Box software, simple and does the job easily of using 2 OS's , if dont like to use then just delete the Virtual drive file. How cool is that ?! cheers