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Windows 7: No Operating System installations found

08 Feb 2012   #11

Windows 7 64-bit

Hitting F12 during BIOS obviously brings up a screen where I can select where to boot from, but it also has a Diagnostics option. I ran that earlier and nothing turned up. Do you think that Diagnostics test is sufficient enough, or would it be most advised to go through the HD manufacturer?

My System SpecsSystem Spec
08 Feb 2012   #12

Windows 7 Home Premium 64 Bit

The HD manufacturer is more reliable since they built the drive and have better utilities for it.
My System SpecsSystem Spec
08 Feb 2012   #13

Windows 7 Pro-x64

Malware can corrupt the MBR and/or UEFI partition too. If you do try to recover files from the disk, be sure to run a scan on it first. If you have a reliable backup of the your files already, you might just try a fresh Windows install.
My System SpecsSystem Spec

09 Feb 2012   #14

Windows 7 64-bit

Ugh, nothing is working. The main issue is that it never recognizes an operating system is installed, so I can never perform any tasks to fix it. I have finally decided to just reformat and reinstall. I was just trying to avoid the hours of reinstalling and setting up programs, but I guess I will have to deal with it. Thanks for all the help.
My System SpecsSystem Spec
09 Feb 2012   #15

Windows 7 Home Premium 64 Bit

I understand your pain. In the future, if you want to avoid having to go through the re-installation of software, you can make system image backups periodically that you may return to if your system stops working. I use Imaging with free Macrium myself, but there is a nice tutorial for the Windows backups in Backup Complete Computer - Create an Image Backup, as well.
My System SpecsSystem Spec
29 Dec 2013   #16

Windows 7 x64
I found this solution

I had this same problem on Windows 7 64 bit machine.

My 1st symptom was unable to boot with "No operating System found" error

Step 1:
boot to Windows 7 recovery disk (use another machine to create one if you don't have one. Must be same windows and same 32 or 64 bits machine)

open command window and run this command to fix the master boot record
bootrec /fixmbr

This would give me one successful boot to windows but the same problem may reoccur if you restart and you will need to repeat above step

Note: Norton scan showed I had Boot.cidox virus and could not remove. Contacted Norton support who told me to run norton power eraser but that found nothing and they had no suggestions other than to pay $100 for technical support.

Here are the steps I performed that actually fixed the problem.

Download and run TdsKiller.exe from

It will detect the virus and prompt you that it needs to reboot to finish cleaning it up

When you reboot, you will need to first boot from the recovery disk again and run bootrec /fixmbr or you will get the unable to find operating system error again.

After you fix the boot record one last time, restart and tdskiller will finish cleaning up the virus. You will see a command window open up while it does this.

After this is complete you can re-run tdskiller and/or norton and it will find no more threats.

Thats it. Hope this helps someone as I spent the better part of a day finding a solution for this.

Note: this was a nasty virus would cause multiple instances of explorer.exe to show up in task manager and they would eat up a lot of CPU time. I would kill them all to make the system more responsive but then I woudn't have a task bar or start button. I would need to run explorer.exe from the file/run menu of task manager to bring it back.
My System SpecsSystem Spec

 No Operating System installations found

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