Post Code Diagnostic cards can display these POST codes, so you can check your PC's progress as it starts and hopefully diagnose errors when the POST stops, though a failure at any given location does not necessarily mean that part has the problem;  it's meant to be a guidepost for further troubleshooting. 

Having obtained a POST code, identify the manufacturer of the chipset on the
 motherboard, then refer to the Tables for advice.

Full Manuals & postcodes are included With our post code
products.

The POST checks at three levels, Early, Late and System Initialization. Early POST
 failures are generally fatal and will produce a beep code, because the video will not be active; in fact, the last diagnostic during Early POST is usually on the video, so that Late failures can actually be seen. System Initialization involves loading configuration from the CMOS, and failures will generate a text message. Consistent failures at that point indicate a bad battery backup.

A POST diagnostic card (or POST card) is an operating system independent expansion card designed to be used with any x86-based computer with an ISA/EISA/PCI  expansion bus 

There are  conversion products for purely Micro Channel and PCI systems, depending on the manufacturer.

DC-ISA-01

For ISA bus with basic error decoding functions

DC-PCI-01

For PCI bus with basic error decoding functions

DC-ISA-01L

 For ISA bus with 4pcs VCC, RST(ReSeT driver), RDY(I/O channel  ReadY), & ALE(Address Latch Enable)LED inductors.

DC-PCI-01L

For PCI bus with 6pcs VCC, GND, FRAME, RST, IRDY, TRDY LED inductors.