Hi clennonuk
When you say 2 lights come on then nothing, is the pc still powered up or do you lose all power?
Well the fiirst thing I would do would try another power supply. Disconnect all connectors from the devices inside the case. Remove the psu. Take another known working one and connect it to your pc. You don't have to actually place it inside the pc you can rest it on the side of the case to just check to see if it's the problem.
I do this all the time and as long as you place the psu where it can't fall inside while testing you will be ok.
If it works then you have solved your problem, if it doesn't, we will need to dig deeper.
Let us know
