[SOLVED] PC randomly shuts down

[PaulTheGamer]

Hello,
I have recently got an upgrade from the old Sapphire Radeon HD 6450, to a Sapphire Pulse Radeon RX 550 4GB. When I download the new drivers and has the GPU installed, it just randomly shut off, only the GPU. Because my fans and CPU were still working. When this occured the first time, I thought it was because my old PSU was only 200W, so I changed It to a 400W one, but the problem still continues. My PC goes on about 40°C when watching YouTube, and when gaming, like Warframe it goes at 60°C. Do you know a fix please?

Thanks in advance, Paul

PC specs:
Intel i3-9100f
8gb ram
400W PSU
1TB HDD
Sapphire Pulse Radeon RX 550 4GB OC

Any other info needed, feel free to ask.

 

[rgd1101]

make and model of this 400w psu?

 

[PaulTheGamer]

make and model of this 400w psu?

I have an Eurocase ATX-400W.

 

[John Chesterfield]

I have an Eurocase ATX-400W.

Replace it with a decent unit, that one is poor.

 

[PaulTheGamer]

Thank you all for trying to help me out. I did try swapping the PSU with my sister's, but it still continued. I then decided to try reinstall windows, because it was bugged because it never updated. So I had an old version of Win10. After reinstalling with a new version, it works perfectly fine. Thanks a lot!