add check if application is running

EnvyUpdate/MainWindow.xaml.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Windows;
-using System.Windows.Shapes;
 using System.IO;
 using System.Net;
 using System.Text.RegularExpressions;
@@ -26,6 +25,11 @@ namespace EnvyUpdate
         public MainWindow()
         {
             InitializeComponent();
+            if (Util.IsProcessOpen("EnvyUpdate"))
+            {
+                MessageBox.Show("Application is already running.");
+                System.Environment.Exit(1);
+            }
             if (!Directory.Exists(appdata))
             {
                 Directory.CreateDirectory(appdata);
@@ -39,7 +43,7 @@ namespace EnvyUpdate
             else
             {
                 MessageBox.Show("No NVIDIA GPU found. Application will exit.");
-                System.Windows.Application.Current.Shutdown();
+                System.Environment.Exit(255);
             }
             if (File.Exists(appdata + "nvidia-update.txt"))
             {

EnvyUpdate/Util.cs

@@ -1,12 +1,9 @@
 using System;
-using System.Collections.Generic;
 using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using System.Management;
-using System.Net;
 using System.IO;
 using IWshRuntimeLibrary;
+using System.Diagnostics;
 
 namespace EnvyUpdate
 {
@@ -86,5 +83,17 @@ namespace EnvyUpdate
             shortcut.TargetPath = targetFileLocation;
             shortcut.Save();
         }
+        public static bool IsProcessOpen(string name)
+        {
+            foreach (Process clsProcess in Process.GetProcesses())
+            {
+                if (clsProcess.ProcessName.Contains(name))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
     }
 }