sql server installation

Please help

I am new to SQL and willing to get a handle on it i have recently installed an evaluation copy which seems to have installed ok, but when i try to start the sql server agent, i get this message: unable to start service sqlserveragent on server . mscorlib

please see error log below

2011-07-05 06:33:54.94 Server      Dedicated admin connection support was established for listening locally on port 1434.
2011-07-05 06:33:55.15 Server      The SQL Server Network Interface library could not register the Service Principal Name (SPN) for the SQL Server service. Error: 0x54b, state: 3. Failure to register an SPN may cause integrated authentication to fall back to NTLM instead of Kerberos. This is an informational message. Further action is only required if Kerberos authentication is required by authentication policies.
2011-07-05 06:33:55.15 Server      SQL Server is now ready for client connections. This is an informational message; no user action is required.
2011-07-05 06:34:12.37 spid10s     Starting up database 'tempdb'.
2011-07-05 06:34:15.60 spid15s     The Service Broker protocol transport is disabled or not configured.
2011-07-05 06:34:15.66 spid15s     The Database Mirroring protocol transport is disabled or not configured.
2011-07-05 06:34:16.55 spid15s     Service Broker manager has started.
2011-07-05 06:34:25.52 spid20s     Starting up database 'msdb'.
2011-07-05 06:34:25.52 spid21s     Starting up database 'ReportServer'.
2011-07-05 06:34:25.55 spid22s     Starting up database 'ReportServerTempDB'.
2011-07-05 06:34:28.85 spid6s      Recovery completed for database ReportServerTempDB (database ID 6) in 1 second(s) (analysis 509 ms, redo 0 ms, undo 494 ms.) This is an informational message only. No user action is required.
2011-07-05 06:34:30.19 spid6s      Recovery is complete. This is an informational message only. No user action is required.
2011-07-05 06:36:11.50 spid13s     A new instance of the full-text filter daemon host process has been successfully started.
2011-07-05 09:03:48.90 spid55      Attempting to load library 'xpstar.dll' into memory. This is an informational message only. No user action is required.
2011-07-05 09:03:48.90 spid56      Attempting to load library 'xpstar.dll' into memory. This is an informational message only. No user action is required.
2011-07-05 09:03:49.29 spid56      Using 'xpstar.dll' version '2009.100.1600' to execute extended stored procedure 'xp_instance_regread'. This is an informational message only; no user action is required.
2011-07-05 09:52:44.87 spid57      Configuration option 'show advanced options' changed from 0 to 1. Run the RECONFIGURE statement to install.
2011-07-05 09:52:44.89 spid57      FILESTREAM: effective level = 0, configured level = 0, file system access share name = 'MSSQLSERVER'.
2011-07-05 09:52:44.93 spid57      Configuration option 'Agent XPs' changed from 1 to 0. Run the RECONFIGURE statement to install.

i have tried to research on the net about resolutions to this query but it still not working

my sqlagent.out file contains info

2011-06-29 19:00:26 - ? [131] SQLSERVERAGENT service stopping due to a stop request from a user, process, or the OS...
2011-06-29 19:00:28 - ? [100] Microsoft SQLServerAgent version 10.50.1600.1 (x86 unicode retail build) : Process ID 9912
2011-06-29 19:00:28 - ? [101] SQL Server HANNAH-ACER version 10.50.1600 (0 connection limit)
2011-06-29 19:00:28 - ? [102] SQL Server ODBC driver version 10.50.1600
2011-06-29 19:00:28 - ? [103] NetLib being used by driver is DBNETLIB.DLL; Local host server is 
2011-06-29 19:00:28 - ? [310] 2 processor(s) and 3000 MB RAM detected
2011-06-29 19:00:28 - ? [339] Local computer is HANNAH-ACER running Windows NT 6.0 (6002) Service Pack 2
2011-06-29 19:00:28 - ? [432] There are 0 subsystems in the subsystems cache
2011-06-29 19:00:28 - ! [000] Failed to load any subsystems. Check errorlog for details.
2011-06-29 19:00:29 - ? [098] SQLServerAgent terminated (normally)

please if anyone can help check this out and advise me on what to do, i'll appreciate it much

thank you