Check whether Ftd2xx DLL exists.

LibreHardwareMonitorLib/Hardware/Controller/TBalancer/TBalancerGroup.cs

@@ -25,25 +25,19 @@ namespace LibreHardwareMonitor.Hardware.Controller.TBalancer
             uint numDevices;
             try
             {
+                if (!Ftd2xx.DllExists())
+                {
+                    _report.AppendLine("Status: missing DLL");
+                    return;
+                }
+
                 if (Ftd2xx.FT_CreateDeviceInfoList(out numDevices) != Ftd2xx.FT_STATUS.FT_OK)
                 {
                     _report.AppendLine("Status: FT_CreateDeviceInfoList failed");
                     return;
                 }
             }
-            catch (DllNotFoundException)
-            {
-                return;
-            }
-            catch (ArgumentNullException)
-            {
-                return;
-            }
-            catch (EntryPointNotFoundException)
-            {
-                return;
-            }
-            catch (BadImageFormatException)
+            catch (Exception e) when (e is DllNotFoundException || e is ArgumentNullException || e is EntryPointNotFoundException || e is BadImageFormatException)
             {
                 return;
             }

LibreHardwareMonitorLib/Interop/Ftd2xx.cs

@@ -14,6 +14,17 @@ namespace LibreHardwareMonitor.Interop
     {
         private const string DllName = "Ftd2xx.dll";
 
+        public static bool DllExists()
+        {
+            IntPtr module = Kernel32.LoadLibrary(DllName);
+            if (module == IntPtr.Zero)
+                return false;
+
+
+            Kernel32.FreeLibrary(module);
+            return true;
+        }
+
         [DllImport(DllName)]
         public static extern FT_STATUS FT_CreateDeviceInfoList(out uint numDevices);