An accident with PSU and a replacement of similar quality

[Gonzo100100]

Hello, I had a strange accident today.
Basically I just run a computer game and after few minutes I got a blue screen. My Windows couldn’t start up so I run my system recovery but then there was an error so I switched off the computer and as I tried to switch it back on I couldn’t. After few attempts the power went off completely in few rooms in my house. So, as the power came back everywhere except in my PSU I searched for a guide how to test my PSU with multimeter but as I wanted to turn the PSU on by putting paperclip wire to green and black cable (as in the guide) it didn’t work so I understand that the PSU is completely broken.
I have two questions:


1. As the PSU didn’t just stop, I had blue screen and system recovery attempt first. Is it possible that something happened first and what caused the PSU to break? If yes, then what are the probable causes?
2. I am sure that as for now PSU is gone for good so can you recommend me a good budged replacement? I had OCZ500MXSP and it was working very well for few years until now so I would be looking for something of similar price and quality but maybe 550W?

 

[Gonzo100100]

Unfortunately, the additional paperclip test didn’t help (after few hours)
So if there is nothing to do then I believe I’ll have to get another PSU I just wonder if I should replace the PSU for another 500W or get 550W just in case of further upgrades, also is PSU something that I should wait for recommendation or anything I get (what has a brand) will be OK?
My current build:

Graphic Card:
- NVIDIA GeForce GTX 970
Motherboard:
- Gigabyte Z77X-UD3H
Processor:
- Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz
RAM:
- 4x Physical Memory 2,048 MB; 1,333 MHz
Power Supply:
- OCZ MODXStream-Pro 500W (broken)
Disk drives:
- C300-CTFDDAC128MAG
- M4-CT512M4SSD2

 

[Gonzo100100]

I don’t know, my budged is not set I want to spend as little as possible but I am also willing to spend as much as necessary. Even my current (OCZ MODXStream-Pro 500W) PSU just broke I am satisfied with it because it was quiet enough and it worked well for few years with no problems. The thing is that there is so many of the PSUs and I don’t know if it matters if I just pick at random so I ask here. I would appreciate if someone who has some knowledge about PSUs (I have 0 probably) could point me something what is just right for my PC specification and is as cheap as possible (again, I don’t want to be scrimp, I want to get the right one for my need – If it was £300 I would buy it but fortunately I know I don’t need to spend anywhere near as much) I believe that I can get a sufficient one for a price between £50-£100