My desktop computer fitted with a Gigabyte GA-81865GME-775 mother board has just suffered what I consider to be an overload shutdown. So severe was this occurrence that the APC UPS also appears to have been damaged.
I became aware that an internal fan was working considerably hard a day or so before the shutdown, but took no notice. However, the following day, I experienced periodic black screens which became more frequent culminating in the final shutdown whilst I was in the process of attempting to access the BIOS in order to investigate.
My suspicion is that one or more components have overheated and accordingly have triggered the shutdown.

My questions are: (a) Where do I start as far as the computer is concerned? And (b) Can the UPS be repaired?
I have checked the battery voltage which is a constant thirteen; however, the re-set switch has not tripped and therefore cannot be re-set. I have also looked inside the unit and have concluded that it is an electronic problem.
I eagerly look forward to your replies.

Hi there. Sorry to hear that your PCs gone down so dramatically - I'm well aware of the frustrations it can cause!

It's not often it happens, but you can check for visible signs of damage on the mobo such as small warping or blackened areas. If there are any found, bin it. Similarly the CPU/cooler, RAM, and all expansion cards. It may be too late now, but use your sense of smell - metallic or burned smells, however faint, are obviously bad signs!

Beyond that, strip the machine to absolute basic parts with NO expansion cards (except video if necessary) and NO drives and try and switch it on. It should boot to BIOS, despite warnings.

If you get nothing, check your PSU and replace if necessary (do you have a spare from another PC?). If that's fine, replace the mobo maybe with a CPU compatible version, or replace the mobo/CPU - don't forget RAM. Logically, if the new mobo won't boot with the old CPU, the CPU's fried. A new mobo and CPU may report RAM errors if you stay with the old RAM. Even if not, a RAM diagnostic would be worthwhile.

Once you've booted to BIOS, and are happy with your mobo/CPU/RAM setup, add back expansions and peripherals one by one - start hard drive, then suggest graphics card, networking, optical drives and so on. If they work, great, if not - they got fried in the disaster.

Never come across this question before! I'd suggest very unlikely, and a replacement was the wiser option than continuing to use an UPS that has already failed.

The problem was not the computer at all, but was in fact the flat screen monitor. After reading nowpc’s response, I back-tracked a little, did a few of the suggested checks but could see or smell nothing suspicious. I therefore decided to power up the system directly from the power supply and sure enough the monitor’s power light did not come on and no matter what I attempted, I could not get it to come on. A technician friend of mine tested it and confirmed that it was indeed faulty; he also said that it was not the inverter, but more of a power problem. The thing is only about three years old.
Having purchased a new monitor, the system is now working perfectly, but I have to admit that I am baffled as to why a faulty monitor should have not only shut down the UPS but also wreck it in the process.
Has anyone any thoughts on the matter?

I guess the UPS did its job in a way - perhaps by saving the rest of your system. On the other hand, it didn't survive, so in some ways you may be lucky you didn't end up with a fire!!

ya really it you were lucky having no fired in the room and even no damage to your system was your luck too man enjoy with your new monitor.