Thanks.
Sadly, label doesn't show PSU's part number, but based on the label layout, i did find out that the PSU is EVGA W1 series,
specs:
https://www.evga.com/products/product.aspx?pn=100-W1-0600-K1
That is a crap quality PSU and most likely behind why your 1st MoBo died. Since when PSU acts up, MoBo is 1st one to die, usually.
Only EVGA N1 and N2 series PSUs are worse than your W1 series, so, there's no high risk of the PSU actually catching fire, as it would be with N1/N2 series. Still, your PSU is bad and new PSU is a must.
Since PSU powers everything, it is
the most important component inside the PC.
With this, NEVER cheap out on PSU! (Which you did.) Also, never buy used PSU either.
Because you have high-end and expensive hardware in use, with GTX 1080 that is 180W but who's transient power spikes can spike to ~400W, new PSU wattage would be:
ATX 2.1/2.5 PSU - 750W (to soak up transient power spikes)
ATX 3.0/3.1 PSU - 650W (it is designed to handle GPU transient power spikes and can sustain double the wattage capacity during the spikes, e.g 650W can sustain 1300W for ~100ms)
As of PSU make/models: good PSUs to go for, are: Seasonic Focus/Vertex/PRIME, Corsair RMx/RMi/HXi/AXi, Super Flower Leadex Gold/Platinum/Titanium.
There are Seasonic Focus and PRIME units that are ATX 3.0. And Seasonic Vertex is ATX 3.0 off the bat.
For other ATX 3.0/3.1 PSUs, further reading:
https://hwbusters.com/best_picks/best-atxv3-pcie5-ready-psus-picks-hardware-busters/2/
As of currently,
i would not power on the PC at all. Since at this moment, you're risking frying your entire PC.
Because the lower the PSU build quality is - the higher the chance of PSU going "boom", releasing magic smoke and frying everything it is connected to (aka your whole PC).
For simplicity sake, i like to classify PSUs into different build quality tiers, whereby:
#1 great quality (e.g Seasonic PRIME, CorsairAXi, Super Flower Leadex Titanium)
Seasonic Vertex, Corsair HXi and Super Flower Leadex Platinum are between good and great quality
#2 good quality (e.g Seasonic Focus, Corsair RMx/RMi, Super Flower Leadex Gold)
#3 mediocre quality (e.g Seasonic Core, Corsair CX/CXm)
#4 low quality (e.g Corsair CV)
#5 crap quality (e.g Seasonic S12III, Corsair VS, EVGA BT/PB/W1/W2/W3/N1/N2)
And for any PC that has dedicated GPU, good quality PSU is minimum, while great quality PSU is preferred.
Now, if PC doesn't have dedicated GPU (e.g office build), then mediocre quality PSU would be minimum, while good quality PSU is preferred.
So, if you want to avoid killing any other hadware in your PC, like your new MoBo or your expensive GTX 1080, new PSU is a must. Else-ways, you're pushing your luck and question isn't if the EVGA W1 blows up and fries your entire PC, but instead when it happens.
Once you have new, good/great quality PSU powering your PC, then you can look towards UPS to protect against blackouts, brownouts and surges, protecting your PC and new PSU further.
In my opinion, every PC should be backed up bu an UPS.
UPSes can output 3 different kinds of waveform:
1. square wave - cheapest of the three. ONLY good for robust hardware, like power generators and motors.
2. simulated sine wave (aka stepped-approximated sine wave) - mediocre price. Good for most home appliances (e.g fridge, washing machine, lights).
3. true/pure sine wave - high price. It is the same as you get out of the wall socket. ONLY waveform good for sensitive electronics, like medical equipment, TVs, PC PSUs.
So, you want to have true/pure sine wave UPS. Simulated sine wave UPS may also work, but it may not. More of that below;
When looking for an UPS, there are 2 things to look out:
1. Output waveform (square wave, simulated sine wave and true/pure sine wave)
2. Design (stand-by, line-interactive and online)
From here you can read about the differences between output waveform,
link:
https://suvastika.com/why-choose-a-sinewave-inverter-ups/
And here are explanations about the UPS design,
link:
https://www.eetimes.com/document.asp?doc_id=1272971
Waveform and design
For PCs, line-interactive UPS would be more than enough since PSUs can easily handle the 2ms to 5ms transfer time of line-interactive UPS.
As far as output waveform goes, true/pure sine wave UPS is best used. While simulated sine wave UPSes are cheaper than true/pure sine wave UPSes, PSUs with Active PFC aren't compatible with simulated sine wave. You might get simulated sine wave UPS running with Active PFC PSU but there can be some major issues. Here's what, how and why.
How do you know which PSUs have Active PFC and which ones don't?
Simple, every PSU that has 80+ certification (e.g 80+ Bronze or 80+ Gold) has Active PFC.
What is Active PFC?
Further reading:
https://en.wikipedia.org/wiki/Power_factor#Power_factor_correction_(PFC)_in_non-linear_loads
What can happen when using simulated sine wave UPS with Active PFC PSU?
When simulated sine wave UPS switches over to the battery power, one of 3 things can happen:
1. UPS displays error resulting PC to shut down immediately.
2. UPS shuts down resulting PC to shut down immediately.
3. UPS switches to battery power resulting PC to power off from UPS (PC stays on).
Why it happens?
Simulated sine wave UPS produces a zero output state during the phase change cycle resulting in a power “gap”. This gap may cause power interruption for active PFC PSUs when switching from AC power output to simulated sine wave output (battery mode).
What to do next?
As stated above, your PC can run off from simulated sine wave UPS but be prepared when you face issues with it. When issues do rise, your best bet would be returning the simulated sine wave UPS and getting true/pure sine wave UPS. Or you can go with true/pure sine wave UPS off the bat.
Wattage
As far as UPS wattage goes, you need to consider the power draw of your PC and monitors. Maybe speakers and wi-fi router too if you plan to plug those into the UPS as well. Though, printers, scanners and other such hardware (full list on your UPS manual) don't plug to the UPS since their startup power draw is way too much for UPS to handle and you can fry your UPS.
Taking PSU's max wattage as a baseline is good idea since it will give your UPS more headroom and you can get longer runtime out of your UPS. Since i don't know what wattage PSU you'd be going for, be it 650W, 750W or 850W but at least one monitor is added on top of it. Depending on the monitor size, they use between 23W to 52W. Wi-fi routers don't consume much power. For example, my Cisco EPC3940L consumes 12V at 3A which means 36W.
Good UPS brands to go for are CyberPower, TrippLite and APC. While there are other UPS brands as well, those three are the best out there.
Note: The more powerful UPS you have, the longer UPS can keep your PC running before it's battery is empty.
My PCs are also backed by UPSes (one UPS per PC) and i have two of these in use:
CyberPower CP1300EPFCLCD (1300VA/780W, true/pure sine wave, line-interactive),
specs:
https://www.cyberpower.com/hk/en/product/sku/CP1300EPFCLCD
This UPS has enough capacity and also outputs true/pure sine wave, so, it should be sufficient for your PC as well.
Or you can also go with the successor model of what i have, namely:
CyberPower CP1350EPFCLCD (1350VA/810W, true/pure sine wave, line-interactive)
specs:
https://www.cyberpower.com/eu/en/product/sku/cp1350epfclcd
This, newer version, is actually the UPS i plan to get, to replace my aging (now 6 years old) UPSes out.