SQL 2005 no longer authenticating a Windows Computer Account instead NT AUTHORITY\ANONYMOUS LOGON

Hi, I have a SQL 2005 server which was in Windows Authentication mode
for SMS 2003, I have changed this to Mixed mode as I have had to put
on some additional DB`s. I also made a mistake and had to restore the
MASTER database (oops!).

Ever since I have restored the MASTER Database I have broken the
security to my SMS 2003 database.

Before the computer account of remote machines were used to connect to
the database, but now the NT AUTHORITY\ANONYMOUS LOGON account is
being used. This was failing with the following error

Error: 18456, Severity: 14, State: 11.

After much play I recreated the 'NT AUTHORITY\ANONYMOUS LOGON' and the
error changed to:

Error: 18456, Severity: 14, State: 16.

If I grant this sysadmin it successfully connects but obviously I do
not want to allow this massive security risk.

The remote computers should be using their Computer Accounts to
connect with Windows Authentication, there is a group in the Master
Database containing these computers which has the correct access to
the SMS database, however it appears as if this is not being used.

Anyone any ideas?