Windows 10: Marked the wrong partition as active

While trying to solve a different problem i followed an article:
You can't install Windows on a USB flash drive from Setup, 0xc1900104
In which i went into disk managment and marked a different partition as active which does not have an OS, how can i revert back to the other partition which worked fine before?

:)

 

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

 

unmark a partition as "active"

Hello Bob,

Thank you for posting your concern in Microsoft Community and welcome to the Windows 10 Family.

Please be informed that marking a partition as active on a basic disk means that the computer will use the loader (an operating system tool) on that partition to start the operating system. An active partition is a partition on a hard drive set as the bootable
partition that contains the operating system. So it is not advisable to configure anything related to boot partition.

Please follow the below steps to unmark the partition as active:

• 
  Open command prompt by pressing Windows key + X and selecting “Command prompt admin”.
  
• 
  Type in diskpart and press Enter.
  
• To identify which disk you need to work with. Type the command: list disk.
  
  This will list all the drives connected to your computer.
• 
  To select the disk enter the command: select disk n
  
  "n" will correspond to the disk # for the ssd you are referring to.
  
• 
  To list all the partitions on the disk enter the command:
  list partition
  
• 
  To select a partition use: select partition n
  
  Substitute "n" correctly and it will select the particular partitions on that drive.
  
• 
  To unmark the current partition as active use the command line:
  inactive
  
• 
  Exit the command prompt using command:
  exit
  
• 
  Reboot the system to let the changes happen.
  

Hope the above information is helpful. If you need further assistance, we would be happy to help you.

Thank you.

 

unmark a partition as "active"

After changing to active partition my computer doesn't boot so what can I do now?