could not load file or assembly, Tried all solution on net - asp.net

Question

Tried every solution found on the net, but still couldn't fix my error:
on 64 bit windows 2008 R2
here my error log:
Server Error in '/npp' Application.
enter code here
Could not load file or assembly 'AjaxControlToolkit' or one of its dependencies. Access is denied.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.IO.FileLoadException: Could not load file or assembly 'AjaxControlToolkit' or one of its dependencies. Access is denied.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Assembly Load Trace: The following information can be helpful to determine why the assembly 'AjaxControlToolkit' could not be loaded.
=== Pre-bind state information ===
LOG: User = Unknown
LOG: DisplayName = AjaxControlToolkit
(Partial)
LOG: Appbase = file:///C:/inetpub/wwwroot/npp/
LOG: Initial PrivatePath = C:\inetpub\wwwroot\npp\bin
Calling assembly : (Unknown).
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\inetpub\wwwroot\npp\web.config
LOG: Using host configuration file: C:\Windows\Microsoft.NET\Framework64\v2.0.50727\Aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework64\v2.0.50727\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Attempting download of new URL file:///C:/Windows/Microsoft.NET/Framework64/v2.0.50727/Temporary ASP.NET Files/npp/13400f43/eee46b06/AjaxControlToolkit.DLL.
LOG: Attempting download of new URL file:///C:/Windows/Microsoft.NET/Framework64/v2.0.50727/Temporary ASP.NET Files/npp/13400f43/eee46b06/AjaxControlToolkit/AjaxControlToolkit.DLL.
LOG: Attempting download of new URL file:///C:/inetpub/wwwroot/npp/bin/AjaxControlToolkit.DLL.
LOG: Using application configuration file: C:\inetpub\wwwroot\npp\web.config
LOG: Using host configuration file: C:\Windows\Microsoft.NET\Framework64\v2.0.50727\Aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework64\v2.0.50727\config\machine.config.
LOG: Post-policy reference: AjaxControlToolkit, Version=3.0.30512.27788, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e
ERR: Failed to complete setup of assembly (hr = 0x80070005). Probing terminated.
Stack Trace:
[FileLoadException: Could not load file or assembly 'AjaxControlToolkit' or one of its dependencies. Access is denied.]
[FileLoadException: Could not load file or assembly 'AjaxControlToolkit, Version=3.0.30512.27788, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e' or one of its dependencies. Access is denied.]
System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) +0
System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +416
System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +166
System.Reflection.Assembly.Load(String assemblyString) +35
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +190
[ConfigurationErrorsException: Could not load file or assembly 'AjaxControlToolkit, Version=3.0.30512.27788, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e' or one of its dependencies. Access is denied.]
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) [phone]
System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +388
System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +232
System.Web.Configuration.AssemblyInfo.get_AssemblyInternal() +48
System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +210
System.Web.Compilation.BuildProvidersCompiler..ctor(VirtualPath configPath, Boolean supportLocalization, String outputAssemblyName) +76
System.Web.Compilation.ApplicationBuildProvider.GetGlobalAsaxBuildResult(Boolean isPrecompiledApp) +283
System.Web.Compilation.BuildManager.CompileGlobalAsax() +50
System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +676
[HttpException (0x80004005): Could not load file or assembly 'AjaxControlToolkit, Version=3.0.30512.27788, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e' or one of its dependencies. Access is denied.]
System.Web.Compilation.BuildManager.ReportTopLevelCompilationException() +76
System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +1012
System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters) +1025
[HttpException (0x80004005): Could not load file or assembly 'AjaxControlToolkit, Version=3.0.30512.27788, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e' or one of its dependencies. Access is denied.]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) [phone]
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +88
System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4355316
Many thanks for your help
I tried to give permission to temporary file, give permission to everyone on iis folder and Temporary file,

Answer 1

It seems to be a file-system permissions error as indicated by
[FileLoadException: Could not load file or assembly 'AjaxControlToolkit' or one of its dependencies. Access is denied.]
The documentation, says you need to give the following file-system permissions to the following users/user-groups.
Inetpub\Adminscripts Administrators Full control
Inetpub\wwwroot (or content directories) Administrators Full control
Inetpub\wwwroot (or content directories) System Full control
Inetpub\wwwroot (or content directories) IIS_WPG Read, execute
Inetpub\wwwroot (or content directories) IUSR_MachineName Read, execute
Inetpub\wwwroot (or content directories) ASPNET Read, execute