The system could not start the server process. Please check the user name and password. (Exception from HRESULT:0X8000401A)

Start-run-cmd, enter Aspnet_regiis.exe-i to reregister IIS

Or

The following error occurred:
Retrieving a component of the CLSID {000209ff-0000-0000-c000-000000000046} in a COM class factory failed because of the following error: 8000401A The system cannot start the server process because the configuration identity is incorrect. Please check the user name and password. (Exception from hresult:0x8000401a).

Solution:
1. Start-dcomcnfg and start Component Services.
2. Locate Microsoft Excel application, Microsoft Office PowerPoint Slides, Microsoft Office Word 97-2003 documents,-Properties-security-customizations, add launch and Activation permissions, Access rights and Add Network service users, giving local start-up and activation;
-Identify, the following users (note, here to select the following users, instead of interactive users, after testing, select interactive users let me depressed for a few days the final problem is not resolved), the user entered the correct current login administrator account and the correct password. The work is done.
3. In the configuration of the Windows Service Application system.web add <identity impersonate= "true" username= "Your user" password= "Your password"/>

It'll work out perfectly.  

The system could not start the server process. Please check the user name and password. (Exception from HRESULT:0X8000401A)