NTDS ISAM error 455, NTDS General error 1168 , General error 1003

Do the following :
1- Follow this guide if you want least loses in your AD database(http://support.microsoft.com/kb/258062/en-us).
I know it's a long guide but in many times it get your job done .

2- If the above guide failed to restore your AD database or you want a hard and direct way to get your AD DC to a working state, follow these steps :
(Warning : these steps aren't guaranteed and data loses may accure )

1- Boot your failed DC with "Directory Services Restore Mode"option

2- Goto "C:\WINDOWS\NTDS\"or "%systemroot%\ntds " , move any *.log files to other folder or delete them

3-Open command prompt .(CMD) :
- Type : esentutl /p %systemroot%\ntds\ntds.dit
*note: if the tool doesn't exist , install the support tools for windows 2003 or windows server 2000

4-Backup "system state" through NTbackup.(just in case you need to restore your DC again ).

5-Go again to "%systemroot%\ntds " and delete or move all files to other folder EXCEPT the following :
-NTDS.DIT
-DROP <--folder

6- Restart your server , and hope it's works for you as it was working for me.

Suggestions and Comments are welcome