How to reset the group policy in user end

hallo sir, i am a system adminstrator

In my server 2008 r2, i have applied group policy setting, un fortunately i applied local adminstrators account disabled thorugh group polcy, at the same time my domain controller also disabled & all local admin also disabled,

i cant logon to the domain admin account in my server because it is disabled, pl give me a solution, how to enable my domain admin (OR) how to reset group policy (OR) how to reset the group policy which was applied through this server in user end.

pl give me suggestions at the earliest, it is very helpful to me