|I cannot find any full specification list or reputable review for that brand/model powersupply.|
Look at the label on the powersupply and provide a list of the Amp ratings on each Voltage rail.
If the fan inside the PSU is very noisy it is a sure sign of poor quality and/or excessive wear. If you have another system fan that will only start spinning if you give it a bit of a push start, that is a sign of under-voltage.
I'm not sure what you mean when you say "It seems that i only built the system 2 days ago so i don't think the problem only recently developed."
Did you or did you not just build this system? Was it built using brand new components?
In all the google searches I have done this brand powersupply appears to have been sold only as part of a Case/PSU package, and many people who bought the case ditched the PSU for something better. I suggest you do the same. It seems to be a cheap light-weight piece of junk that will only put the rest of your system at risk.
Goin' Fishin' (Some day)