Diagnostic software is almost never used in the repair business especially when a device is dead and does not power on. I used to use Tech Tool Pro and ASD for Mac but never used anything for windows.

Motherboard schematics and board diagrams are much better when troubleshooting rather than other software.

You can buy a pc-multimeter form Germany for about 1200euros. The idea is you need a known good board to save the results on your pc and when you get the same board in for a repair, you just use the test points and the software gives you a pass or fail. The system is very good if you plan on working industrial.