well you can try to reset file/registry permissions:
Please select the correct security template from MS article below.
On a domain controller, run
secedit /configure /db c:\windows\temp\seceditsv.
sdb /cfg
"c:\windows\security\templ
ates\DC security.inf" /log c:\windows\temp\seceditsv.
log
On a non-domain controller, run
secedit /configure /db c:\windows\temp\seceditsv.
sdb /cfg
"c:\windows\security\templ
ates\setup
security.inf" /log c:\windows\temp\seceditsv.
log
For more detailed info on each security template check:
http://support.microsoft.com/default.aspx?scid=kb;EN-US;816585