A project can only be deleted if it is at proposal status, and if no timesheets or expense entries exist.
Delete a project by:
Open the project you want to delete.
Click the edit button in the read only view on the project details tab.
Click the actions button in the top right and select 'delete' from the list.
Click the 'delete' button on the confirmation page.
You are now returned to project list which is refreshed to show that the project has been deleted.
Tip: Once the project is active, or has attached transactions or invoices then it cannot be deleted. Try changing the project status to complete or unsuccessful to hide it from the default project list view.