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uninstall primary partion

onyourmark asked
Last Modified: 2012-05-10
I had a Vista setup. I then installed Win 7 on another partition. I want to remove vista and just use the Win 7. I tried deleting the partition but I get this message:
"windows cannot delete the active system partition on this disk"

Can anyone suggest what I can do?
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You can't use Windows Explorer to remove an active Widows partition.  There are a few options where you can remove Vista:

1) Do a clean install of Windows 7.  During installation process, delete the unwanted Vista partition.
2) Use a bootable DOS program to access the partition and the remove it.  Mark the Windows 7 partition to "active".  Please read info at http://www.bootdisk.com/popfiles.htm to create a CD DOS bootable.  When you boot your system into DOS, you can remove the partition and then mark the Windows 7 as "Active Partition".  This is a very quick process; however, you should read the instructions carefully.

Either way, make sure that you backup your data on your system first.  Back them up on a DVD or external hard drive.

If I were you, I would select option 1 which is easier and a clean install always a best.  Windows 7 does not take that long to install anyway.

Good luck
Most Valuable Expert 2015

First of all, within Windows 7 does the drive letter it is installed appear to be drive C: or drive D:? If it is Drive D:, then don't remove the other partition, as Windows 7 will then no longer work properly. If you remove the first partition Windows will then think it is now Drive Letter C:, and because all registry entries etc will point to letter D:, it won't find most of the things it is looking for.

If on the other hand the system drive letter in Windows 7 appears as drive C:, it might work, but you'll still have to boot with the Windows 7 DVD and perform a repair with it so it can correct the mbr and other settings.


Hi Vista is on C and Win 7 is on D. What do you mean by doing a clean install? Do you mean on the Vista drive C or on D? Will I loose my data on D which currently has Win 7 and is the system I want to preserve?
Most Valuable Expert 2015

So when you boot to Windows 7 it show the drive it is on as Drive D? If that is the case, you won't be able to do this without installing from scratch.


Sorry. I got it backwards. I don't know why I said that. WIn 7 is on C and Vista is on D.
Most Valuable Expert 2015

Just to clear up any doubts, attach screenshots of your diskmanagement and also of what you see in "My Computer". Do that for both OS's (and mention which is which).


Hi. Here it is.

From the image you sent, your Windows 7 is not an active/bootable partition.  On the other hand, your Vista partition is showing as active/bootable and it is D.  My suggestion would be put your Windows 7 CD/DVD again and start the installation from scratch.  When the system prompts to select the partition to install, delete both C and D partitions and re-create new partitions.  Install on the first available partition.

Copy your data to an external USB or CD/DVD before delete your data.

If you need more details, please ask.

Good luck.


Hi. If I do that won't I loose all the programs in Win 7? I did not want to do that.
Most Valuable Expert 2015

OK, first of all, I see you have a "Recovery Partition". That generally means your PC came preinstalled with Vista, and probably you didn't get any CD's or DVD's with your PC to install it from in case of an HD crash. Most PC's that are factory setup this way have a utility installed which will allow you to create a set of recovery media so you can restore the system to factory defaults in such a case. If you haven't already created those media (I know most people don't because they are unaware of this), I very strongly recommend you first boot into Vista and check your PC manufacturer's help to create those media. If ever you want to sell the PC in the future, you will want to sell it with it's original OS, so things stay legal. This is just a recommendation from me though. But you'd have to do this before you blow away your Vista installation, as that utility will only be available there.

After that, boot your PC with the Windows 7 DVD, and allow it to go to the page where it show you the partitions, where you can tell it to install the OS to what. Here you should be able to delete the Vista Partition, and also to set the Windows Partition to "Active". When that is done, try rebooting the PC without the DVD inside. With some luck it'll boot into Windows 7 straight away, if not it might Ask you whether you want to allow it to repair the system. If that is the case, allow it to. If you can't boot Windows 7, boot again with your Windows 7 DVD, and there you should have an option to do a repair (It's on the same screen where you can select "Install", but it's rather a small option at the bottom of the screen.


Hi. Thanks very much. I am still a little confused. In your second paragraph are you saying that I am going to install an OS or just that I go to that part of the install process and in there I can delete Vista?
Most Valuable Expert 2015
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Great. Thanks for your considerate help.

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