I use to keep my home office window open because there are some cross fresh air. I will need to close the window and use some dehumidifyer, maybe some air conditioner.
I tried to clean with some isopropilic alcohol, changed PSU, isolated components and finally a computer store tested it too. I have a power line stabilizer but maybe I will buy an UPS because of the inverters isolation. I dont overclock and I dont change components often. One possible reason is oxidation but I dont see any major oxidation in the mobo.
Maybe this kind of mobo is good for datacenters not homes.
I am loking for a cheap Asus Tusl2-c, it is half or lesss the price of a new DDR mobo here in Brazil and I still have the CPU/memory.