about uninstallation

You need to boot to the Win7 install CD and reinstate the bootloader. You removed the Grub config so the loader doesn't know what to do. You should post on a windows forum to find how to get the bootloader back

To see how to restore the Ubuntu/XP/Vista/7 bootloader, go on this site

http://ubuntuforums.org/showthread.php?t=1014708

sir would like to please tell me in detail about grub(it's structure and
purpose )and how can i uninstall on dual boot systems another one is
windows7 or windows xp with out lost the partitions please help me
On Mon, Jul 11, 2011 at 12:15 AM, delance <
<email address hidden>> wrote:

> Your question #164248 on grub2 in Ubuntu changed:
> https://answers.launchpad.net/ubuntu/+source/grub2/+question/164248
>
> delance proposed the following answer:
> To see how to restore the Ubuntu/XP/Vista/7 bootloader, go on this site
>
> http://ubuntuforums.org/showthread.php?t=1014708
>
>
> If this answers your question, please go to the following page to let us
> know that it is solved:
>
> https://answers.launchpad.net/ubuntu/+source/grub2/+question/164248/+confirm?answer_id=1
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
> https://answers.launchpad.net/ubuntu/+source/grub2/+question/164248
>
> You received this question notification because you asked the question.
>

Grub is the bootloader, it's made in three parts;
1st sector of boot disk, which is run by BIOS and gave control to second part
63 following sector, which is able to read file system, and access to third part
/boot/grub which contains many boot files
You don't need to uninstall Grub, as it's not an application. You must overwrite it with Windows bootloader.
About partition that could be lost, it's most a Windows issue, because it's linked to the ability of Windows to reinstall itself properly.
And a very very good idea is to make a backup an an external media.
To learn about Grub: https://help.ubuntu.com/community/Grub2

sir thank you for giving me nice information and i want one help in my
system i have windows 7 and ubuntu few days before i deleted the ubuntu
partition (in computer management in that memory management ) then when i
restarted my system it shows like "grub rescue >"
so my problem is how can i restore my windows 7 with out installing windows
7 is there any commands for that or is there any boot loader which detects
windows 7 partition please help me
On Sun, Jul 17, 2011 at 4:16 PM, delance <
<email address hidden>> wrote:

> Your question #164248 on grub2 in Ubuntu changed:
> https://answers.launchpad.net/ubuntu/+source/grub2/+question/164248
>
> delance posted a new comment:
> Grub is the bootloader, it's made in three parts;
> 1st sector of boot disk, which is run by BIOS and gave control to second
> part
> 63 following sector, which is able to read file system, and access to third
> part
> /boot/grub which contains many boot files
> You don't need to uninstall Grub, as it's not an application. You must
> overwrite it with Windows bootloader.
> About partition that could be lost, it's most a Windows issue, because it's
> linked to the ability of Windows to reinstall itself properly.
> And a very very good idea is to make a backup an an external media.
> To learn about Grub: https://help.ubuntu.com/community/Grub2
>
> --
> You received this question notification because you asked the question.
>

delance has already given the answer in comment #2 above, 10 days ago:

Look at http://ubuntuforums.org/showthread.php?t=1014708 below the red subtitle "How to restore the Windows Vista or 7 bootloader" or the subtitle "How to restore the Windows XP bootloader". You need your Windows XP/Vista/7 recovery disk.

There is no need to bother about the grub structure, as that is related to Ubuntu and not to Windows (and as far as I can see you want to get rid of Ubuntu but keep just Windows 7).