regmatlabserver not working, !matlab -regserver does though - what is the difference?

I am trying to make Matlink (<http://matlink.org/>) work using Matlab 2013a and Mathematica 9 and while it works well on one computer, on my second computer the command

regmatlabserver

,run as admin from in the Matlab command prompt, doesn't seem to do register Matlab as an Automation Server. After lots of trying, I found someone posting the following command

!matlab -regserver

,run as admin from in the Matlab command prompt, and it does the trick. I can successfully connect with Mathematica. I find the information in the help files insufficient and I do not really understand why one command works while another doesn't. More specifically, what is the difference between

regmatlabserver, !matlab -regserver

and

enableservice('AutomationServer',true)?

Based on the help files, they presumably all do the same thing...

Thanks for clarifying,

Erik

Update:

Unfortunately, the solution posted above wasn't reproducible. However, starting the automation server manually will do it:

"C:\Program Files\MATLAB\R2013a\bin\matlab.exe" /Automation

I thought the issue might be related to the fact that I had an older version of Matlab installed before. Using the function from here I confirmed that the COM Server version is the correct one:

The default Automation Server for "MATLAB.Application" on this machine is: ProgId: Matlab.Application (Version 8.1) LocalServer32: C:\Program Files\MATLAB\R2013a\bin\win64\MATLAB.exe /MLAutomation CLSID: {8DE84D10-9F9D-4D03-ABC0-B5C2F63F7492} File exists: 'C:\Program Files\MATLAB\R2013a\bin\win64\MATLAB.exe'