The sqlservr.exe file for the instance has not been found

This error occurs when Microsoft SQL Server has been removed before, and there was an error during that procedure. It is possible that the Windows Registry has not been cleaned up properly, causing some leftover files to stay on your computer. Installing the program afterwards might fail as the file sqlservr.exe can not be found.®

In order to resolve this error, you must completely remove any components of Microsoft SQL Server before installing again.

How to remove Microsoft SQL Server 2008 in Windows XP or Windows Server 2003

On the desktop, click Start - Control Panel - Add/Remove programs.
Select Microsoft SQL Server 2008 R2 from the list and click Change/Remove.
Click Remove.
Select to remove the instance MAMUT and click Next.
Note! MAMUT is the default name for the instance and is suggested during the installation. If you have chosen another instance, you need to replace MAMUT with the name you have chosen.
Click Select All to select all components and click Next.
Click Next and then Remove.
Once the procedure has been completed, press [F5] on the keyboard to update the list of installed programs.
Uninstall any remaining programs belonging to Microsoft SQL Server.
Once done, restart the computer.
After restarting the computer, open Windows Explorer and browse to the folder C:\Program Files.
Rename or remove the folder Microsoft SQL Server.

You can now start the installation of Mamut Business Software again. Read more below if you get the same error again.

How to remove Microsoft SQL Server 2008 in Windows Vista and newer or Windows Server 2008 and newer

On the desktop, click Start - Control Panel - Programs and Features.
Select Microsoft SQL Server 2008 R2 from the list and click Change/Remove.
Click Remove.
Select to remove the instance MAMUT and click Next.
Note! MAMUT is the default name for the instance and is suggested during the installation. If you have chosen another instance, you need to replace MAMUT with the name you have chosen.
Click Select All to select all components and click Next.
Click Next and then Remove.
Once the procedure has been completed, press [F5] on the keyboard to update the list of installed programs.
Uninstall any remaining programs belonging to Microsoft SQL Server.
Once done, restart the computer.
After restarting the computer, open Windows Explorer and browse to the folder C:\Program Files (x86).
Rename or remove the folder Microsoft SQL Server.

You can now start the installation of Mamut Business Software again.

If you receive the same error again when trying to install Mamut Business Software, you must remove Microsoft SQL Server manually. Please note that in this case you must create a backup of any applications using Microsoft SQL Server. Read more about manually removing Microsoft SQL Server here on Microsoft's website.