PSU is a Huntkey ATX 12v/ 220v-50Hz,A4
BINGO! The 4850 recommended minimum requirements are 450W and 30A. Just take those specs along with you and find a 450W PSU and make sure it can handle 30A on the 12V rails. If the PSU has more than 1 12V rail, as in it will say 12V1 12V2, etc, you will want to look at the 12V wattage. It is usually printed on the PSU under the 12V rail ratings. Take that wattage and divide by 12v, that will give you the combined amperage rating. ex. on a 450W PSU it might say 12v1=18A, 12V2=18A, and then under that 360W. 360W/12V=30A. You will want a 12V wattage rating of 360W or above. Depending where you hail from you will have different selections. Jyjjy's list is all good, there are alot of other good brands but these are populate. Thermaltake, BFG, Coolermaster(some of them), Enermax, FPS, Zalman, and several others. There is alot of preference in the PSU market to. Alot of people will point you to Corsair, but there are alot of GOOD PSU's out there, and even MORE bad ones.
99% sure this is your problem.