If you don't have the Job Costing module enabled, you will not be able to delete the project itself. But if you unOK the order, you should be able to delete the Project from the field on the order. If you want to delete the Project record itself, you can go into System>>Settings>>Configuration>>Verticals, and tick Job Costing. Go to the Job Costing module, open the Projects register, then open the project and delete it (Record>>Delete). Then go back to Configuration and untick Job Costing.

Newer versions of Enterprise and Standard ERP can detect whether you have Job Costing enabled, and if you don't, the options to create project and project budget are removed from the Operations menu.

Regards

Paul Timms
IT System Integrators Ltd