Rotting roots

[mokey41]

I bought 4 orchids about 2 years ago purely because they were pretty and on sale at Walmart. Once they were done blooming I put them into my north facing bay window and really didn't pay that much attention to them. One of them died last winter but the other 3 seemed to just stay the same.

I did a bit of research at that time and discovered they were in moss and most of the roots were rotten. I trimmed them up and repotted in bark. Since then 2 more have just rotted away. The remaining plant has one nice root, one so so root and has grown a kei kei with no roots at the very base of the original flower spike.

Any advice on possibly saving this poor survivor? Will it be able to grow with only one root? How can I encourage it to grow more roots? I read on here about sphag and bag but not sure just how to go about it or if it would be helpful.