ArsStudio_YT

Yea I'm going with their recommendations. It's either a damaged PSU or board. If you have a spare PSU it'll be easily to definitively check. Doesn't even need to be a powerful PSU. Even a 250W will do nicely if you have one. Just remove the GPU and boot off the onboard graphics. (Just for diagnostic purposes).

Alright, I think i know what I should do now, thanks a lot. 

IMO, yes, it's a bit hot.
You can get a good, short enough aftermarket cooler like Cryorig M9i for less than $20

I probably forgot the thermal paste. Anyway, thanks for replying. I'll check out the cooler if applying thermal paste doesn't do any good...

I probably forgot the thermal paste. Anyway, thanks for replying. I'll check out the cooler if applying thermal paste doesn't do any good...

Well, this is kinda unfortunate. The only cards that I know of that it will fit here are special nVidia Quadro cards. Like THIS. 
Also, Gigabyte launched a small one, but unfortunately its mounting stuff is too bog for you: LINK
If you are familiar with tools, I recommend modding the case, so you can mount a card verticaly instead of horizontaly (fan facing towards you, cards back to case's back). With this, you could mount any GPU. 
Good luck, I hope it helped.

Banned

Review your workbench... It'll be awesome. (No offence|No joke)
Or possibly Luke's workbench.

We don't ban new members

Thanks man... Appreciate it..

Thanks man... Appreciate it..

What? Why? I thought new members could say Hi here.!! 

Hi

Ban him! Ban everyone! 
Hi