In SQL 7.0, seven (7) errors are kept in the Mssql7\Log subdirectory. When you start SQL Server:

    ErrorLog.6 is deleted.
    ErrorLog.5 is renamed ErrorLog.6.
    ErrorLog.4 is renamed ErrorLog.5.
    ErrorLog.3 is renamed ErrorLog.4.
    ErrorLog.2 is renamed ErrorLog.3.
    ErrorLog.1 is renamed ErrorLog.2.
    ErrorLog is renamed ErrorLog.1.

The current session will log to ErrorLog.

To increase the number of error logs, use Regedt32 to navigate to:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer

On the Edit menu, Add Value name NumErrorLogs, as a type REG_DWORD. In the DWORD Editor, click the Decimal Radix and enter a number greater than 7.