All services are gone on Central Administration

Urgent,

We have a prod server (windows server 2008r2 SP1) with Sharepoint 2010 (signal farm) and database is on another server(windows server 2008r2 SP1) with SQL 2008R2. Today I found from  the CentralAdministration, all services on application server are gone. Application server is not showing anymore. I try to open a web application, I got error with correlation ID, but  fortunately, there is no LOGS, and from event view the error are:

"There are no instances of the Word Automation Services started on any server in this farm. Ensure that at least one instance is started on an application server in the farm using the Services on Server page in Central Administration."

And

"Event 6398 (SharePoint Foundation) of severity 'Critical' occurred 7 more time(s) and was suppressed in the event log"

Any ideas?

Thanks a lot

PS Looks like the application server is disconnected from the farm, but what puzzles me is some sites on the sharepoint farm are working and some are not, and on the central administration, DB server is showing, but Application Server and services are all disappeared. Help please!!!