The computer does not start after you change the active partition by using the Disk Management tool

[gabrielmedeiros]

I was formatting my USB Stick in the Disk Management Tool and by mistake I put it as an active partition, after reading what it meant I also made my C: partition active thinking I was undoing the mistake. After restarting my PC, windows shows a message it could not find any OS.

 

[BFG-9000]

The active partition needs to be the boot partition, which on a clean Windows install to a blank disk is usually a small 100MB separate partition from C: that is not assigned a drive letter. And you can have an active partition on every drive, so if you wanted to ever boot from that USB, it would have to have its own active partition.

Either boot to a bootable drive utility on CD or USB, or put the drive into another computer with a working Windows and change the active partition back to the 100MB one. If you are posting from a phone and have no other PC to use or download from, then booting from the Windows Install media and selecting Startup Repair might be able to fix it.

Alternately, many drive utilities allow you to move the boot files to your main partition, into a folder called \boot (this is what normally happens if you install Windows to a drive that is already partitioned and holds data). Then you could delete the 100MB partition and merge its empty space into the main partition if you like.

 

[gabrielmedeiros]

The active partition needs to be the boot partition, which on a clean Windows install to a blank disk is usually a small 100MB separate partition from C: that is not assigned a drive letter. And you can have an active partition on every drive, so if you wanted to ever boot from that USB, it would have to have its own active partition.

Either boot to a bootable drive utility on CD or USB, or put the drive into another computer with a working Windows and change the active partition back to the 100MB one. If you are posting from a phone and have no other PC to use or download from, then booting from the Windows Install media and selecting Startup Repair might be able to fix it.

Alternately, many drive utilities allow you to move the boot files to your main partition, into a folder called \boot (this is what normally happens if you install Windows to a drive that is already partitioned and holds data). Then you could delete the 100MB partition and merge its empty space into the main partition if you like.

Perfect answer. Windows install media startup repair worked, thanks for explaining about active partition