This looks to me like Bacterial Brown Spot. The only good way to get rid of it is to cut the plant down to about 1 or 2 inches of stem only. Make sure you sanitize your cutting knife between cuts with a bleach water solution. You don't want to spread it and it easily spreads to other orchids. So the quicker you cut the bulk of the plant down the better. Toss the cut off portions quickly and carefully.
Looks like she'll grow back fine and healthy. Bacterial infections can happen rather quickly and was probably introduced unknowingly.
There are other treatment options, but they are tough to get to work after the infection has spread rapidly (like in your case). Other options at early onset of bacteria... copper fungicide, baking soda water mixture (I think 4 teaspoons per gallon of water) or horticultural oil.
Just cut off what plant it left and let the new shoot start over. Best wishes on a healthy recovery!!
Thank you @bdmillergallery for the advice on how to deal with my dying orchid.
I have cut off the affected plant as you suggested. I will give it some time and see how the new plant does. I was thinking of re-potting it. But I might just let it be. Thanks, once again!