SharePoint 2007:Cannot connect to the configuration database.

Question

The share point 2007 server under Windows Server 2008 R2 runs well formerly, but suddenly the user can't visit the site with error on page:
Cannot connect to the configuration database.
I also checked windows log with bellow main errors：
Log Name:      Application
Source:        Office Server Search
Date:          2015/2/28 22:30:47
Event ID:      10034
Task Category: Gatherer
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      ***
Description:
Could not access the Search service configuration database.
Context: Application 'b9f7f366-4027-4923-b5ce-b93c132df7c3'
Details:
 Unspecified error
 (0x80004005)
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Office Server Search" />
    <EventID Qualifiers="49152">10034</EventID>
    <Level>2</Level>
    <Task>3</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2015-02-28T14:30:47.000000000Z" />
    <EventRecordID>2323514</EventRecordID>
    <Channel>Application</Channel>
    <Computer>***</Computer>
    <Security />
  </System>
  <EventData>
    <Data>
Context: Application 'b9f7f366-4027-4923-b5ce-b93c132df7c3'
Details:
 Unspecified error
 (0x80004005)</Data>
  </EventData>
</Event>
======================================
Log Name:      Application
Log Name:      Application
Source:        Windows SharePoint Services 3
Date:          2015/2/28 22:30:50
Event ID:      5586
Task Category: Database
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      ***
Description:
Unknown SQL Exception 64 occured. Additional error information from SQL Server is included below.
A connection was successfully established with the server, but then an error occurred during the login process. (provider: TCP Provider, error: 0 - The specified network name is no longer available.)
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Windows SharePoint Services 3" />
    <EventID Qualifiers="0">5586</EventID>
    <Level>2</Level>
    <Task>484</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2015-02-28T14:30:50.000000000Z" />
    <EventRecordID>2323517</EventRecordID>
    <Channel>Application</Channel>
    <Computer>***</Computer>
    <Security />
  </System>
  <EventData>
    <Data>64</Data>
    <Data>A connection was successfully established with the server, but then an error occurred during the login process. (provider: TCP Provider, error: 0 - The specified network name is no longer available.)</Data>
  </EventData>
</Event>
==================================================
Source:        Windows SharePoint Services 3
Date:          2015/2/28 22:31:00
Event ID:      27745
Task Category: General
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      ***
Description:
The description for Event ID 27745 from source Windows SharePoint Services 3 cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on
the local computer.
If the event originated on another computer, the display information had to be saved with the event.
The following information was included with the event:
#50071: Unable to connect to the database SP_Config on ***.  Check the database connection information and make sure that the database server is running.
the message resource is present but the message is not found in the string/message table
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Windows SharePoint Services 3" />
    <EventID Qualifiers="14130">27745</EventID>
    <Level>2</Level>
    <Task>1105</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2015-02-28T14:31:00.000000000Z" />
    <EventRecordID>2323520</EventRecordID>
    <Channel>Application</Channel>
    <Computer>***</Computer>
    <Security />
  </System>
  <EventData>
    <Data>#50071: Unable to connect to the database SP_Config on ***.  Check the database connection information and make sure that the database server is running.</Data>
  </EventData>
</Event>
Please kindly support to find the root cause and guide how to fix it ASAP.
Many appreciations for your hellp in advance!
Note:
1)As checked, SQL server service is running well;
2)Web server log under the path C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\12\LOGS with bellow errors:
03/02/2015 11:25:53.28  mssearch.exe (0x0F0C)                    0x08FC Search Server Common         
 GathererSql                    0 Monitorable CSqlCrawl::ExecuteCommand() Failed in GetSession, Error is 0x80004005 - File:d:\office\source\search\search\gather\server\gatherobj.cxx
Line:9654 
03/02/2015 11:25:53.39  mssearch.exe (0x0F0C)                    0x08FC Search Server Common           Common                       
 0 Monitorable Application b9f7f366-4027-4923-b5ce-b93c132df7c3, resource 1: pIDBInitialize->Initialize error. Failed to create a non fast load session. - File:d:\office\source\search\search\searchdll\resourcemanagerimpl.cpp Line:608 
03/02/2015 11:25:53.39  mssearch.exe (0x0F0C)                    0x08FC Search Server Common           Common                       
 0 Monitorable CResourceManager::CreateSession Error creating non fastload session 'Provider=SQLOLEDB;Extended Properties='Server=***;Database=SP_SharedServices_Search;Trusted_Connection=yes;App=Windows SharePoint Services;Timeout=15';'. - File:d:\office\source\search\search\searchdll\resourcemanagerimpl.cpp
Line:658 
03/02/2015 11:25:53.39  mssearch.exe (0x0F0C)                    0x08FC Search Server Common           UtilCommon                   
 0 Monitorable Dumping error record [0]:   Source: Microsoft OLE DB Provider for SQL Server   HRESULT: 0x80004005   Code: 11   Description: [DBNETLIB][ConnectionRead (recv()).]General network error. Check
your network documentation. - File:d:\office\source\search\common\pkmutild\atldbext.cxx Line:1250 
03/02/2015 11:25:53.39  mssearch.exe (0x0F0C)                    0x08FC Search Server Common           GathererSql                  
 0 Monitorable CSqlCrawl::ExecuteCommand() Failed in GetSession, Error is 0x80004005 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:9654

Answer 1

Hi,
In this forum we mainly discuss questions and feedbacks about Office products, since your question is about SharePoint, I suggest you post the question in SharePoint forum to get further assistance:
https://social.technet.microsoft.com/Forums/office/en-US/home?category=sharepoint
The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction with us. Thank you for your understanding.
Regards,
Melon Chen
TechNet Community Support
It's recommended to download and install
Configuration Analyzer Tool (OffCAT), which is developed by Microsoft Support teams. Once the tool is installed, you can run it at any time to scan for hundreds of known issues in Office
programs.