Help! Two orchids but only one is sick!??
 

So I am extremely NEW at Orchids! I'm not even entirely sure what exact kind of Orchid I have...

I just got it probably about a month and a half ago.

When I first bought it the stem on the right had 3 flowers and a small bud. The stem on the left was all buds. Everything was fine until I watered it for the first time and the very next day all the buds on the stem on the right started to fall off and all the buds on the stem on the left started budding.

I know Orchids lose their flowers eventually so I just thought maybe it was normal but when the stem started dying I thought maybe it was getting too much light. I really wasn't sure but where I had it located the stem on the right was getting a little more light so I have since moved it to a different location where they both get the same amount.

Nothing has changed. The stem on the right is still very slowly turning brown and the stem on the left seems to be doing great (althought I haven't noticed too much growth in the one new bud at the top).

How is it that only one of them is dying if they're in the same pot and are receiving all the same care!??

Should I trim the stem on the right down to the first green node??

What should I do! :(

You have a Phalaenopsis orchid, and if it did not come with a cultivar tag, then it's a no i.d. (or NOID). Blooms usually last about 6-8 weeks, so it might have been time for them to drop and the stem to dry up. Sometimes the stems will stay green and push out another branch, but sometimes they dry up. Since you have another spike still in bloom, I would cut the other stem all the way to the base of the plant (as close as you can get it without cutting the plant).

Also, I don't think light will really affect the stems. An indication of too much light will be reflected in the leaf color. If you're pushing the boundaries of light intensity, sometimes the leaves will become reddish tinged or pale greenish yellow. Most of my phals have a apple green leaves with a slight reddish tinge, but I like to push the limits on light to make sure they're getting enough. Dark green leaves usually indicate orchid needs more light.

As for watering, be sure to water with lukewarm water.

Once the other flowers drop, I would recommend repotting to fresh medium. This will allow you to get a good look at the roots to make sure it has a healthy root system. What is it currently potted in? If it's in moss, you will want to water when the moss dries (maybe every 10 days to 2 weeks). If it's in bark, maybe once a week. Since I don't know your growing conditions, it's hard to be more specific. I would advise to err on the cautious side with watering to avoid overwatering.

Here is a link to Phalaenopsis care. A sunny east windowsill is a great place for phals. AOS | Phalaenopsis

Good luck and welcome to Orchid Board!

Pretty sure you have ONE orchid- Phalaenopsis. With TWO spikes. ;)
Grasshopper gave you all the info you need.