It's not clear exactly what program is having trouble with .net Framework, but it looks like Dell Support Center is at least part of the problem (if not all of it) - both the reference to "system diagnostics" and the actual "imstrayicon.exe" point in that direction. Uninstall Dell Support Center from Programs/Features and see if the error goes away.  It's not a necessary program - and is prone to being buggy, especially when it tries to update itself - but if you want it back you can download and install it again from your Drivers and Downloads - Applications section on support.dell.com.   
I'm getting this Microsoft .NET Framework error. I've read some of the posts on this forum and my error report seems a little different. My Dell XPS L501X came with Windows 7. SP1 is installed. I have an HP printer, not Dell (if that relates). Please assist. Microsoft .NET Framework Unhandled exception has occurred in your application. If you click Continue, the application will ignore this error and attempt to continue. If you click Quit, the application will close immediately. The system cannot find the file specified. See the end of this message for details on invoking just-in-time (JIT) debugging instead of this dialog box. ************** Exception Text **************System.ComponentModel.Win32Exception: The system cannot find the file specified   at System.Diagnostics.Process.StartWithShellExecuteEx(ProcessStartInfo startInfo)   at System.Diagnostics.Process.Start(ProcessStartInfo startInfo)   at imstrayicon.MainForm.ReadRegistry()   at System.Windows.Forms.Timer.OnTick(EventArgs e)   at System.Windows.Forms.Timer.TimerNativeWindow.WndProc(Message& m)   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) ************** Loaded Assemblies **************mscorlib    Assembly Version: 2.0.0.0    Win32 Version: 2.0.50727.5446 (Win7SP1GDR.050727-5400)    CodeBase: file:///C:/Windows/Microsoft.NET/Framework64/v2.0.50727/mscorlib.dll----------------------------------------imstrayicon    Assembly Version: 6.0.5830.12    Win32 Version: 6.0.5830.12    CodeBase: file:///C:/Program%20Files/Dell%20Support%20Center/imstrayicon.exe----------------------------------------System    Assembly Version: 2.0.0.0    Win32 Version: 2.0.50727.5442 (Win7SP1GDR.050727-5400)    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll----------------------------------------System.Windows.Forms    Assembly Version: 2.0.0.0    Win32 Version: 2.0.50727.5446 (Win7SP1GDR.050727-5400)    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll----------------------------------------System.Drawing    Assembly Version: 2.0.0.0    Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400)    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll----------------------------------------System.Management    Assembly Version: 2.0.0.0    Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400)    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Management/2.0.0.0__b03f5f7f11d50a3a/System.Management.dll----------------------------------------System.Xml    Assembly Version: 2.0.0.0    Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400)    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll---------------------------------------- ************** JIT Debugging **************To enable just-in-time (JIT) debugging, the .config file for thisapplication or computer (machine.config) must have thejitDebugging value set in the system.windows.forms section.The application must also be compiled with debuggingenabled. For example:        When JIT debugging is enabled, any unhandled exceptionwill be sent to the JIT debugger registered on the computerrather than be handled by this dialog box.
Microsoft .NET Framework error