i have installed a ubuntu9.10 by bootup a cd ...now i wanna to uninstall it.. plz help me to uninstalled ubuntu completly

You don't uninstall OS's, you just delete the partition/s. Try booting on a live cd and using fdisk or parted to delete the relevant partitions

Simply deleting the partition may sound like the right answer, and it is the thing to do in the end. However, there is one consideration. Ubuntu, like many distros, installs it's own boot loader (GRUB) and, depending on what other OS you have on your system, will likely store the config files for grub on it's own partition. If you simply delete that, then you will not be able to boot up.

You will need to fix your MBR. If you are using linux, there are a couple of options. First, most linux installs will set up the bootloader for you. If you are not re-installing, then you can use the command line. IIRC, that should be grub-install.

However, if your main OS is windows, it will be different. First, boot up with an install CD and enter manual recovery mode (in XP, press "R" after it is fully loaded). Then at the command prompt you can try fixmbr. I think that you don't need any arguments, buty ou might want to look up the details, as I'm not that familiar with Windows.

Amrit;
It appears that you have NEVER posted any follow-up in any of your 34 threads----not even a "thank you". Since you never respond to the people who try to help you, I am one of many members who will not try to help you.

Double post as well: http://www.linuxquestions.org/questi...roblem-802525/

As others have pointed out, you NEVER respond to ANY of the questions you post. Plus you double post questions (this one, for instance), don't spell your words out, and can't write or ask a clear question.

You want to know how to uninstall it? Go buy Windows, put the disk in, and follow the instructions. Go bother folks on a Microsoft forum.