Dear Diego,

I checked where you said, there is nothing defined there, but as I start some of my servers with "local system acount" and as I know it means running...

Thanks for your attention.

event error ID is : 103

The error message in event log is:" SQL Server Agent could not restart. Reason: Unable to connect to  local server."

Thank you very much Jo Pattyn,

I changed the specified services to manual and then could install the service pack...

I have installed SQL sever 2000 + SP4, but as I have installed Analysis services, I want to install SP4a to upgrade my OLAP server... I've not installed SP4a yet