How to get Adobe Reader full path(including executable file name)?

One of these should do it for you:

    var adobe = Registry.LocalMachine
                        .OpenSubKey("Software")
                        .OpenSubKey("Microsoft")
                        .OpenSubKey("Windows")
                        .OpenSubKey("CurrentVersion")
                        .OpenSubKey("App Paths")
                        .OpenSubKey("AcroRd32.exe");

    var path = adobe.GetValue("");

    var adobeOtherWay = Registry.LocalMachine
                                .OpenSubKey("Software")
                                .OpenSubKey("Classes")
                                .OpenSubKey("acrobat")
                                .OpenSubKey("shell")
                                .OpenSubKey("open")
                                .OpenSubKey("command");

    var pathOtherWay = adobeOtherWay.GetValue("");

Pick one and run with it ;)

I found a problem with the "adobeOtherWay" solution. If Adobe Acrobat(not reader) is installed, then the path will point to Acrobat.exe and not the reader's exe.(I wanted to comment to above, but don't have enough reputation)

I'm using : HKEY_CLASSES_ROOT\Software\Adobe\Acrobat\Exe It gives me the full path and exe- name of the installed Acrobat Reader, just what you need.