Implemented check to see if a given registry value exists.

DisableNvidiaTelemetry/Controller/NvidiaController.cs

@@ -120,7 +120,10 @@ public static IEnumerable<NvidiaControllerResult<TelemetryRegistryKey>> Enumerat
                     error = ex;
                 }
 
-                yield return new NvidiaControllerResult<TelemetryRegistryKey>(telemetryRegistryKey, error) {Name = key.Name};
+                if (key.exists())
+                    yield return new NvidiaControllerResult<TelemetryRegistryKey>(telemetryRegistryKey, error) { Name = key.Name };
+                else
+                    yield return new NvidiaControllerResult<TelemetryRegistryKey>(null, new RegistryKeyNotFoundException($"Failed to find registry key: {key.Name}"));
             }
         }
 

DisableNvidiaTelemetry/DisableNvidiaTelemetry.csproj

@@ -102,6 +102,7 @@
     <Compile Include="Controller\NvidiaController.cs" />
     <Compile Include="Controller\NvidiaControllerResult.cs" />
     <Compile Include="MarginSetter.cs" />
+    <Compile Include="Model\RegistryKeyNotFoundException.cs" />
     <Compile Include="Model\ITelemetry.cs" />
     <Compile Include="Model\TaskNotFoundException.cs" />
     <Compile Include="Model\TelemetryRegistryKey.cs" />

DisableNvidiaTelemetry/Model/RegistryKeyNotFoundException.cs

@@ -0,0 +1,16 @@
+using System;
+
+namespace DisableNvidiaTelemetry.Model
+{
+    /// <summary> Represents an exception where a registry key could not be found. </summary>
+    public class RegistryKeyNotFoundException : Exception
+    {
+        public RegistryKeyNotFoundException()
+        {
+        }
+
+        public RegistryKeyNotFoundException(string message) : base(message)
+        {
+        }
+    }
+}

DisableNvidiaTelemetry/Model/TaskNotFoundException.cs

@@ -3,7 +3,7 @@
 namespace DisableNvidiaTelemetry.Model
 {
     /// <summary>
-    ///     Represents an exception where a secheduled task could not be found.
+    ///     Represents an exception where a scheduled task could not be found.
     /// </summary>
     public class TaskNotFoundException : Exception
     {

DisableNvidiaTelemetry/Model/TelemetryRegistryKey.cs

@@ -127,6 +127,27 @@ public Replacement(Regex regex, string replacment)
             public string Replacment { get; }
         }
 
+        /// <summary>Check to see if the value exists.</summary>
+        /// <returns>True if it exists, false if not.</returns>
+        public bool exists()
+        {
+            var subKey = SubKey;
+
+            try
+            {
+                if (_useRegex)
+                    ValueExpressions.Select(vd => vd.Value.Match.IsMatch(subKey.GetValue(vd.Key).ToString())).FirstOrDefault();
+                else
+                    ValueStrings.Any(vd => subKey.GetValue(vd.Key).ToString() == vd.Value.Enabled);
+            }
+            catch (System.NullReferenceException)
+            {
+                return false;
+            }
+
+            return true;
+        }
+
         #region Implementation of ITelemetry
 
         public bool IsActive()