If you done any modifications in the domain controllers group policy for computer section, Try to update the GP by using gpupdate command. And also u need to restart the DC to apply the new changes. Check for any errors related to GP in Event Viewr.
Hope this will work for u…
If u still facing the prob.. possible give the report of RSOP and Event Viewr..
I have run RSOP and I can see that one portion of the policy is not running on the DC. I made a change to the DC and it replicated to the others. I checked for the change on these three DCs and it took place. I believe the policy is being replicated to my other domains. It appears as though something is blocking the security part of the policy.