How to set value ProjectSuite.TestItems.TestItem(1).Enabled? If possible

no this properties are read only

It's read only, but there's a feature request to make it read-write:
http://community.smartbear.com/t5/TestComplete-Feature-Requests/make-read-write-the-quot-enabled-quot-property-of-a-testitem-in/idi-p/106019