Here is how to enable the health reports for SharePoint 2010.
You might get this message when clicking on it under Central Admin monitoring:
a health report is not available for this site. usage processing may be disabled on this server
On Central Admin goto "Manage Services on Server"
Make sure that the following to are started:
"Web Analytics Data Processing Service"
"Web Analytics Web Service"
Then goto Monitoring and Review Job Definitions
You need to change the Service to "Microsoft SharePoint Foundation Usage" and enable it.
Once enabled run it.
Check the report again