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Windows 7: no OS found

20 Jan 2014   #1

Windows 7 Home
no OS found

Hello everybody,

I installed Windows 7 on a used PC (HP XW4600) recently.
This PC contains 2 Harddisks (1 Samsung and 1 WDC).
My idea was to install the OS on the Samsung and to use this drive for data too.
I intended to use the WDC for backup only and to disconnect it normally.

After installation everything works OK untill I take the WDC from the BIOS list of devices to boot from.
Then the computer does not start up: it will give the message "no OS found".

Disk Management gives the results as given in the attachment.

no OS found-disk-management.jpg

For those who do not speak Dutch:
Schijf 0=Samsung, Schijf 1=WDC, Opstarten=boot.

Note that volume Y (on WDC) is "system" and volume C is "boot"!

My question is:
what should I do to have the computer starting normally with the WDC disk disconnected?

My System SpecsSystem Spec
20 Jan 2014   #2
Microsoft MVP


The System boot files are on the wrong HD. This can happen when all other HD's are not unplugged during install.

The solution is to Mark C Partition Active,

power down to unplug the other HD,

boot into Win7 DVD or System Repair Disk to run Startup Repair - Run 3 Separate Times until Win7 starts and C holds the System flag.

Now you can plug back in the other HD making sure Win7 HD remains set first HD to boot in BIOS setup. Mark Y partition Inactive: Partition - Mark as Inactive - Windows 7 Forums. This should keep it from ever interfering but if it does move the data off to wipe it with Diskpart Clean Command before repartitioning in Disk Mgmt.
My System SpecsSystem Spec
20 Jan 2014   #3
Microsoft MVP

Vista, Windows7, Mint Mate, Zorin, Windows 8

And if you are lazy like me, you can do this. Make sure you understand the warning in the tutorial.

Bootmgr - Move to C:\ with EasyBCD
My System SpecsSystem Spec

21 Jan 2014   #4

Windows 7 Home

I have followed the instructions as given by GregRocker: using the System Repair Disk and run Startup Repair.

This action has resulted in the situation I wished: the WCD drive may be disconnected without having a problem at startup. And also after reconnecting it the system starts normally.

Disk Management gives now:
- for partition C attribute System is added
- for partition Y attribute System is removed.

Thank you very much.
My System SpecsSystem Spec

 no OS found

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