Why does MATLAB fail to launch on AMD64 machine running Windows?

MATLAB has been the software of my love and need in my engineering education, even my final undergraduate thesis work was done by using a lot of MATLAB. Sadly, the AMD64 processor family is not supported on Windows for any version of MATLAB prior to Release 14 Service Pack 3 (R14SP3). And I had the AMD64 pretty much half  the time I was in Engineering School at NSU. Unfortunately, there are no current editions of MATLAB available here on Dhaka yet, so we don’t have the option to upgrade to solve this! It took me 6 months just to figure out where is the issue and another 3-4 months to come up with something that works. I was very close by going through the MATLAB help section online: but honestly, that online how to was the hardest how to to find, and was even harder to follow. So here’s my one:

BLAS stands for Basic Linear Algebra Subroutines. It provides the key foundations for performing mathematical computations in MATLAB. Everything which works with vectors or matrices, from simple matrix-vector multiplication to solving large systems of linear equations, depends on the BLAS routines. In some cases MATLAB will choose to use a version of BLAS different than one you may want or need to use. Each version is specifically optimized for a specific processor, but sometimes (for newer processors or various tasks) you may want to choose to use a different version of BLAS.

In order to work around this issue, you need to set the BLAS_VERSION environment variable to the following:

Right click on My Computer, Properties> Advanced Option> Environment Variables.

Set name of the the variable as BLAS_VERSION and Variable Value as $MATLAB\bin\win32\atlas_Athlon.dll (where $MATLAB is the directory you have installed MATLAB).

Worst case scenario: If you have set the BLAS_VERSION and still receive an error, add the following two lines to the end of your “blas.spec” file:

AuthenticAMD Family 15 Model 12 atlas_Athlon.dll # Athlon 64 (Newcastle)

AuthenticAMD Family 15 Model * atlas_Athlon.dll # AMD64

**Not 100% Guranteed to solve the issue on all systems**

The “blas.spec” file can be found in the directory $MATLAB\bin\win32.
Of course, “%MATLAB” here is the path where you installed MATLAB.

** This solution worked for me
on Windows Xp and Vista in both 32 and 64 bit environment.
Mind it that these old MATLAB may run on 64 bit OS,
but works as a 32bit app using WoW64!