Error:

The SQL Server service failed to start. For more information, see the SQL Server Books online topics, “How to: View SQL server 2005 setup log files” and “starting SQL Server Manually.” Error 29503

Error Message:

Causes:

1. SQL Server needs administrative permissions to create registry entries and to create services.
2. The firewall on the system might be blocking the installation.
3. Application Log files in the Event viewer is full. Increase the size of the Log files.
4. The SQL 2005 express edition does not support following processors AMD K6-2 processors, AMD Phenom 8400 Triple-Core processor, And Intel Xeon X5680.
5. Required prerequisites for SQL Express 2005 may not be there in system.
6. Antivirus on the system might be blocking the installation.

Don’t click on cancel, let that error message be on screen, and Follow the workarounds 

Workaround 1

Let the error message be on the screen, Transfer [SqlOS.dll and SqlServr.exe of SqlFix] to SQL installation path [C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Binn] and click Retry.

Download: SqlFix

Workaround 2:

• Make sure that you are currently logged in to system as Administrator account.
• Before installation of SQL Server pause or disable the antivirus
• Switch OFF the “Firewall”

Click Start | Run | type firewall.cpl | Switch Off | Click OK.

• Make sure that you are running the SQL Server setup as “Run as Administrator”. (If applicable)
• During SQL Server installation choose “Local System” for Service account.

Workaround 3: [For Windows XP]

Give “EVERYONE” full control permissions to “Protect” folder

Select Show hidden files and folders

Navigate to: “C:\Documents and Settings\NetworkService\Application Data\Microsoft”

And Give “EVERYONE” full control permissions.

Workaround 4:

Don’t click on cancel, let that error message be on screen, try to rename “Microsoft” folder in the below path.

Select Show hidden files and folders

“C:\Documents and Settings\NetworkService\Application Data\Microsoft”

Workaround 5:

Create an “empty” registry key name as ‘Domain’:

Click Start | Run | type regedit | Click OK.

Navigate to:

“HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameter”

Right Click “Parameter” | New | String Value | rename as “Domain”

Workaround 6:

Increase the Event viewer log size to bigger value.

Click Start | Run | type eventvwr.msc | Click OK.

Right click Application > Properties > Change maximum log size to bigger value.

And Check “Overwrite events when needed”.

Click Apply and OK.

Workaround 7:

Software requirements for SQL Server 2005 express sp2:

Microsoft .NET Framework 2.0

Windows Installer 3.1

Microsoft Data Access Components (MDAC) 2.8 SP1 or later.

Microsoft Internet Explorer 6.0 SP1

Workaround 8:

The SQL 2005 family does not support following processors AMD K6-2 processors, AMD Phenom 8400 Triple-Core processor, And Intel Xeon X5680.