Desktop Mining Rig Update 2

So I thought of just adding GPU & PSU to an old desktop of mine to turn it to a mining rig and to minimize the cost but turns out to be a bad idea due to below factors.

Motherboard has only 1x PCI Express slot so only one GPU can be used with this system no matter what.

RAM supported by Motherboard is DDR2.

Power Supply is 400watt but its condition is not at its best right now.

So it is a far better idea to build the cheapest mining rig possible but with new components. I am currently looking around for optimized mining rig component combination & will post here once I find something viable...