please read until end before starting recovery! After searching all the web I found a method to reset a Toshiba satellite L500-1UR to factory settings. Before I want to describe the approach I will summerize my starting situation.

I got the laptop from my brother. The boot manager was changed while another Windows Version was installed. So the option Toshiba HDDRecovery in the options of "repair computer" or the option itself after pressing F8 at boot time wasn't available. Fortunately, he didn't delete the "HDDRecovery" folder on its DATA partition, so all factory images were available. To install I needed a method to apply an image installation. This is possible with the Windows 7 recovery CD you can download it for example here .

Boot this CD, start a command prompt. The way to do this is described here .

At command prompt you change to the partition with the HDDRecovery folder. At my brothers laptop it was:

D:\HDDRecovery

In a sub-folder you will find the command line tool "imagex". At my brothers laptop it was located in:

D:\HDDRecovery\ODDFiles\Tools

On the other hand, you need the image files. These files were located in

D:\HDDRecovery\SWImg\

and ended with .swm . swm-files are splited wim-files, the Microsoft format for image files. For your problem you must locate your "imagex" and your swm-files. On my brothers laptop there were 6 files

10656XSP.swm
10656XSP2.swm
10656XSP3.swm
10656XSP4.swm
10656XSP5.swm
10656XSP6.swm

Now, the recovery is very easy:

change to folder were imagex is located. Here

D:
cd D:\HDDRecovery\ODDFiles\Tools

1. format the WINDOWS partition (mostly C:) on the command line with
format c: /fs:ntfs /q /V:WINDOWS

2. Apply recovery image to C: with the command, for my brothers laptop:

imagex /ref D:\HDDRecovery\SWImg\10656XSP*.swm /apply D:\HDDRecovery\SWImg\10656XSP.swm 2 C:\

the option /ref says imagex the location of the splitted images, expressed with a wildcard
the option /apply says imagex the location of the first image

the number "2" represents the second image inside of the swm-files, here the image for the WINDOWS partition

C:\ says imagex on which partition it should apply the image.

Perhaps your SYSTEM partition has to be reset to, so you have to do the same steps for it. I did it without formating it by:

imagex /ref D:\HDDRecovery\SWImg\10656XSP*.swm /apply D:\HDDRecovery\SWImg\10656XSP.swm 1 C:\

WARNING: I found out the image number by executing:

imagex /ref D:\HDDRecovery\SWImg\10656XSP*.swm /apply D:\HDDRecovery\SWImg\10656XSP.swm * C:\

The use of the wildcard (*) led to an error, so the command throw an XML-File plot were I found the correct image number for the partitions.

Now you have write back the factory image to your partition(s). Perhaps it is necessary to reinstall the bootmanager. If you get the error:

"NO BOOTMGR"
at startup, you have to use the recovery CD a second time. Now, you can choose the option
"Startup Repair" in the same menu where you found the option "Command Prompt".
It will find out that no bootmanager is installed and will repair it.

So, I hope I could help anyone.

Last but not least, this describtion comes without warranty. I am not responsible for any errors or faults or lost data of your HDD. Please backup your important data to e.g. an external storage.