MacPro early 2006 not connecting to monitors
My MacPro early 2006 (an "obsolete" machine according to Apple support, but loaded with hard-to-replace programs) is not connecting through DVI to either one of two monitors. The machine turns on but the monitors receive no signal. The local repair shop said (sight unseen) that there were different possibilities for the malfunction. Can somebody suggest ways to narrow it down? Thanks.
Mac Pro, Early 2008, early 2006, late 2013