If it has lost all its leaves but is still flowering, then I would cut the flower spike off ASAP in order to save the plant. Given careful attention (watch out for overwatering!) it MAY send up an offset or two from the stump that remains...which you can then pot up separately when they grow new roots of their own. The reason you should remove the flower spike is that it's draining precious energy from your plant which it will need to produce a new offset or leaf.
It also seems to me that you may have gone from one extreme to another with regard to lighting intensity. It's clear from the sunburn you describe that your orchid really got zapped by some overly intense sunlight, but for future reference you may find that growing it "inside near a window with shades" may actually be too low lighting. I grow my Phals in the winter up against the glass (no shades) of a south west (more west than south, really) facing window--here in Maryland that's enough light for them to bloom without any worry of leaf burn. In the summers they go outside on my shady deck where they get a few hours of morning sun, til about 9:30 a.m.
By the way, why not pick up a new Phal in bloom for you to enjoy while this one regenerates? It may take a long while for it to recover and you ought to have something enjoyable to look at while it does.
-Claire