We had a request from one of our clients to check why the Site Usage report stopped updating for 2 months now. When we started to check for causes we tried to check if the configurations were still set, then we tried to check the services and . . . well let me just tell you that the Sharepoint Services Search and Timer were stopped!!! Well, this happened because the system administrator of this client changed the password of the MOSS admin.
So the solution was simple, just updated the identity information on the services and started them . . .