get substring in SQL Server 2005

Hello all,
I need to get all the strings in between ''(sdf,adf,satish,rajesh,satish)from a table containing the below mentioned strings. I have used fn_trace_gettable to get this information from a trace file.

1)Login failed for user 'sdf'. The user is not associated with a trusted SQL Server connection. [CLIENT: <local machine>]
2)Login failed for user 'sdf'. The user is not associated with a trusted SQL Server connection. [CLIENT: <local machine>]
3)Login failed for user 'satish'. The user is not associated with a trusted SQL Server connection. [CLIENT: <local machine>]
4)Login failed for user 'rajesh'. The user is not associated with a trusted SQL Server connection. [CLIENT: <local machine>]
5)Login failed for user 'satish'. The user is not associated with a trusted SQL Server connection. [CLIENT: <local machine>]




I have unsuccesfully tried instr and substring functions of SQL SERVER2005 to get this information.


Thanks in advance


cheers,
Satish