I upgraded to Windows 8.1 Pro today and reinstalled all of my software. I'm having issues with the new Java JDK (v40). I can't compile anything on the command line. I keep getting the following error message: javac is not recognized as an internal or external command So I went back in and checked the Environmental Variables and everything is set correctly. When I check the PATH via the command prompt, I get the following: C:\WINDOWS\system32>path PATH=C:\Program Files (x86)\Intel\iCLS Client\;C:\Program Files\Intel\iCLS Clien t\;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\WINDOWS\system32;C: \WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C: \Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\ Intel\Intel(R) Management Engine Components\IPT;C:\Program Files (x86)\Intel\Int el(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Man agement Engine Components\IPT;C:\Program Files (x86)\MATLAB\R2012a Student\bin;C :\Program Files\Condusiv Technologies\ExpressCache\;C:\Program Files\Java\jdk1. 7.0_40\bin; I triple checked and everything is using the correct path. I even reinstalled the JDK and get the same error. Any thoughts?