johntwoods

I am needing to upgrade my legitimate version of Windows 7 Home Premium to Windows 7 Professional so I can utilize at 16gb of extra RAM I installed.
 
Total RAM is 32gb, but Windows 7 Home Premium ceiling is 16gb.
 
So, I am trying to find my options for upgrading specifically to Windows 7 Professional.  I would very much like to not have to do a clean install, as I have some many pieces of software installed and set up properly for use.
 
Anytime Upgrade doesn't seem to be much help.  
 
What are my options in regards to what I am looking to do?  Any guidance on what to purchase and where to do this properly would be appreciated.
 
thanks in advance.