permissions - php 5.5 can read and write but wont execute -

so have executable i'm trying run on desktop. gave proper permissions user read write , execute. php can write file , read file, wont execute .exe. here's found in research

• safe_mode set on in case have configure safe_mode_exec_dir
• the parent directory blocking php executing .exe
• the path incorrect

in php 5.5 there no safe_mode, looked in php.ini sure. if can read , write directory have correct path, , wouldn't blocking php accessing either. weird thing got work before in same directory setting had have gotten changed somewhere. there other common problems why php can read , write not execute .exe? line of code i'm using is:

exec("c:\users\myname\desktop\folder\myexecutablename.exe");