CERTSRV - error 500 internal server error

Hello, dear all,
I have a problem with IIS 6^

On domain server installed Windows Server 2003 R2 SP2. I installed
Certification Authority few months ago. After that I installing some web
applications (Sharepoint services) - and delete it. After that site
http://\certsrv give me error "500 internal server error".
Certification Authority doesn't support reinstalling - in that case I lost
some important information.
How could I fix that problem.? where should I seek for my mistake?

--
Vsevolod V Shevchuk