A user was instructed by their software support to upgrade a program and install SQLExpress as part of the installation process.

Since that time, the service has been able to start, citing error 17053, which appears to be an authentication issue.

Here is the error log:

2011-01-11 13:17:45.50 Server      Microsoft SQL Server 2005 - 9.00.3042.00 (Intel X86) 
    Feb  9 2007 22:47:07 
    Copyright (c) 1988-2005 Microsoft Corporation
    Express Edition on Windows NT 5.1 (Build 2600: Service Pack 2)

2011-01-11 13:17:45.50 Server      (c) 2005 Microsoft Corporation.
2011-01-11 13:17:45.50 Server      All rights reserved.
2011-01-11 13:17:45.50 Server      Server process ID is 3332.
2011-01-11 13:17:45.50 Server      Authentication mode is WINDOWS-ONLY.
2011-01-11 13:17:45.50 Server      Logging SQL Server messages in file 'c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\LOG\ERRORLOG'.
2011-01-11 13:17:45.52 Server      This instance of SQL Server last reported using a process ID of 2332 at 11/10/2010 2:15:24 PM (local) 11/10/2010 7:15:24 PM (UTC). This is an informational message only; no user action is required.
2011-01-11 13:17:45.52 Server      Error: 17053, Severity: 16, State: 1.
2011-01-11 13:17:45.52 Server      UpdateUptimeRegKey: Operating system error 5(Access is denied.) encountered.
2011-01-11 13:17:45.52 Server      Registry startup parameters:
2011-01-11 13:17:45.52 Server        -d c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\master.mdf
2011-01-11 13:17:45.52 Server        -e c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\LOG\ERRORLOG
2011-01-11 13:17:45.52 Server        -l c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\mastlog.ldf
2011-01-11 13:17:45.52 Server      Error: 17113, Severity: 16, State: 1.
2011-01-11 13:17:45.52 Server      Error 3(The system cannot find the path specified.) occurred while opening file 'c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\master.mdf' to obtain configuration information at startup. An invalid startup option might have caused the error. Verify your startup options, and correct or remove them if necessary.
2011-01-11 13:17:45.52 Server      Error: 17053, Severity: 16, State: 1.
2011-01-11 13:17:45.52 Server      UpdateUptimeRegKey: Operating system error 5(Access is denied.) encountered. 4 Server      Error: 17053, Severity: 16, State: 1.
2011-01-11 13:08:21.34 Server      UpdateUptimeRegKey: Operating system error 5(Access is denied.) encountered. 12:47:20.85 spid5s      SQL Trace ID 1 was started by login "sa".
2011-01-11 12:47:20.90 spid5s      Starting up database 'mssqlsystemresource'.
2011-01-11 12:47:20.93 spid5s      The resource database build version is 9.00.3042. This is an informational message only. No user action is required.
2011-01-11 12:47:21.21 spid5s      Error: 15466, Severity: 16, State: 1.
2011-01-11 12:47:21.21 spid5s      An error occurred during decryption.
2011-01-11 12:47:21.38 spid8s      Starting up database 'model'.
2011-01-11 12:47:21.38 Server      Error: 17182, Severity: 16, State: 1.
2011-01-11 12:47:21.38 Server      TDSSNIClient initialization failed with error 0x5, status code 0x90.
2011-01-11 12:47:21.38 Server      Error: 17182, Severity: 16, State: 1.
2011-01-11 12:47:21.38 Server      TDSSNIClient initialization failed with error 0x5, status code 0x1.
2011-01-11 12:47:21.38 Server      Error: 17826, Severity: 18, State: 3.
2011-01-11 12:47:21.38 Server      Could not start the network library because of an internal error in the network library. To determine the cause, review the errors immediately preceding this one in the error log.
2011-01-11 12:47:21.38 Server      Error: 17120, Severity: 16, State: 1.
2011-01-11 12:47:21.38 Server      SQL Server could not spawn FRunCM thread. Check the SQL Server error log and the Windows event logs for information about possible related problems.

One lead I had was to change the SQL logon account from "Network Service" to "Local System".

Unfortunately, that is resulting in the error message The Security ID Structure is Invalid [0x80070539]

Any help either uninstalling or getting SQLExpress running would be fantastic.