Windows 10: Installed a second windows 10 os on the same partition

I mistakenly installed a second windows 10 os on the same partition and now my laptop cannot boot into windows. I want to get rid of both of them and reinstall windows 10. What do I do?

:)

 

Windows 10

no, you can't go back..
I suggest creating a backup image of your os drive

 

W7 Hard drive partition issue

to get rid of that 100 meg windows partition that setup creates for you on a new install on a blank hdd:

- press shift+f10 when on the partition management screen in setup <-- this opens a command prompt
- diskpart <-- start the windows command line partition management tool
- list disk <--- list the installed hdds in this computer for the next step
- select disk 0 <- might have to replace 0 with the number of the correct disk
- clean <-- this will erase all data on the disk you selected one step up- dont use the wrong disk!
- create partition primary <- creates a primary partition taking up all space on the drive, adjust the command if necessary
- exit, exit to exit diskpart and the command prompt
- click refresh in partition manager and select your newly created partition and install to that

 

Installing Windows Vista/7 on a GUID Partition Table

I've never tried multiple partitions so this is a shot in the dark...

At step #10, I would try setting the size parameter (it is in mebibytes) to how large you want the partition windows is installed on to be, then go ahead and install windows. This will leave the rest of the drive raw instead of consuming it into the OS partition (C drive). Once you successfully boot into Windows, you should be able to use Computer Management -> Disk Management to create partitions in the raw space.


If you really wanted to do it with diskpart before Windows is installed, you basically repeat the following lines making sure to specify a size if you don't want it to consume all remaining space:

• create partition primary size=size in mebibytes here
• format quick fs=ntfs label="appropriate name here"
• assign letter=C thru Z here

Obviously, you can use quick formatting or leave it out for full format. Leave off the size parameter when you reach the final partition that should consume all the remaining space. Also remember that the order you do this in goes from the outside of the disk (where it is fastest) to the inside of the disk (where it is slowest). Because of this, it is recommended to put EFI (e.g. size=300), then MSR (e.g. size=300), then Windows (e.g. size=30000), then Applications (e.g. size=70000), then Storage (e.g. no size parameter).

If I'm right, the above example would look like this:

• diskpart
• list disk
• select disk <id>
• online disk
• attributes disk clear readonly
• clean
• convert gpt
  
• create partition efi size=300
  
• create partition msr size=300
  
• create partition primary size=30000
• format fs=ntfs label="Windows"
• assign letter=C
  
• create partition primary size=70000
• format fs=ntfs label="Applications"
• assign letter=D
  
• create partition primary
• format fs=ntfs label="Storage"
• assign letter=E
• exit