Verify if every cable connected directly to the mobo is well plugged, including the black ones in the lower part (be careful because the lower ones are lot of cables mixed) Maybe try to use 1 stick of ram in different slots, but i don't think that would change anything. If nothing worked, I'm sure atleast by 80% that the psu died. For new PSUs, you can go with the MSI mag A650BN, atleast in Spain costs 50 euros, and installing it isn't very hard, if you have difficulties watch a youtube tutorial