I tired to follow the Instructions for the DotNetNuke Install Package and got no errors that I knew of.  But when I tried to access http://localhost/WEBSITENAME I Got the error below.  GDQ is my WEBSITENAME.  I'm sure it's a simple error, but I'm not IT expert and don't know any.  The reason I was using DNN is I thought it was for non-IT pros.

Could not load file or assembly 'ClientDependency.Core' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.Server
Error in '/GDQ' Application.

Could not load file or assembly 'ClientDependency.Core' or one of its
dependencies. This assembly is built by a runtime newer than the currently
loaded runtime and cannot be loaded.
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.BadImageFormatException: Could not load file or
assembly 'ClientDependency.Core' or one of its dependencies. This assembly is
built by a runtime newer than the currently loaded runtime and cannot be loaded.

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 'ClientDependency.Core' could not be loaded.

WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1.
Note: There is some performance penalty associated with assembly bind failure logging.
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].

Stack Trace:

[BadImageFormatException: Could not load file or assembly 'ClientDependency.Core' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.]
   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

[Configurati sException: Could not load file or assembly 'ClientDependency.Core' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.]
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +11241896
   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.CodeDirectoryCompiler.GetCodeDirectoryAssembly(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories, Boolean isDirectoryAllowed) +11231074
   System.Web.Compilation.BuildManager.CompileCodeDirectory(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories) +185
   System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +551

[HttpException (0x80004005): Could not load file or assembly 'ClientDependency.Core' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.]
   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 'ClientDependency.Core' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +11335894
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +88
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4355316

Version Information: Microsoft .NET Framework Version:2.0.50727.5466; ASP.NET
Version:2.0.50727.5456