Phalaenopsis leaves, yellow, black at base

[Pollycat76]

I have had my Phalaenopsis for a year and a half. It has not bloomed since the original bloom faded. It grew two large strong green leaves earlier this year, but then suddenly three weeks ago, two leaves near the base turned yellow and at the same time there seemed to be a dreaded soft black spot where they joined the base. The leaves fell off very quickly and the remaining part of the leaves dried up. Now the same thing thing is happening to the very lowest leaf. There are some green roots showing in the pot, plus brown ones. There are strong greeny/grey air roots above the bark surface. The bark feels quite dry at the top of the pot.
Is there anything I can do to save this plant ?