Somebody can please help me for making my old PC into a gpu mining rig.

My PC specs.

Motherboard : gigabyte GA-M68MT-S2
2 PCIE slots : 1 PCIEx16 & 2 PCIEx1
Processor : AMD Phenom ii x6 1045T
Hard drive : 1TB HDD
Ram : 4gb
PSU : 200W

I am going to buy 2 asus rog strix gtx 1080 ti OC will it work on my built ?
Do I need to modify or completely upgrade to a new system ?
Also can I go with 1 gtx titan volta instead of 2 asus strix gtx 1080 ti oc ?