My orchid is a year old and has first shed all its blooms, and then most of its leaves. I cut the stem down to a few inches above the root and applied cinnamon powder on the open cut as advised on a website. Now only 2 elongated leaves remain and the roots are looking dry too. I have moved the orchid from my kitchen window to the bathroom window now. Please help me revive it, if it's still possible to do so.

The first thing you need to do is look through the Orchid Forums within the NGA website. Several threads refer to growing Phalaenopsis orchids. That is the type of orchid you have.
Your plant is suffering from a lack of water. The mix it is in is too coarse and it is not holding enough water.
Phalaenopsis do not tolerate any sunshine, like to be moist and never dry out. They should be re-potted every year as they respond well to re-potting.
Commercial mixes are available on line from various sources or from a place like Home Depot or Lowe's.

It is normal for the flowers to die back after a month or two. You were right to cut back the flower spike. However, it is not normal for leaves to be dying on your Phalaenopsis.

The plant appears to be potted in very large bark chips. That is fine, but the larger chips do not retain water very well so the Orchid usually needs more frequent watering. You didn't mention your watering routine, but my educated guess is that you are losing leaves because the roots are not getting adequate water.

Once or twice per week, take the inner plastic pot to the sink and let warmish water flow through the bark chips for a minute or so. Of course, there has to drain holes in that pot for the excess water to flow through. Never let the inner pot sit in water that has collected in the bottom of the outer pot.

A sunny north window is best.

Your orchid is a Phalaenopsis. You have either overwatered or underwatered - the results look the same, as in both cases the roots are compromised. In Photo #2, the roots to the left are plump and green (under the bark, they would be white). Those roots are healthy. The shriveled roots to the right are dead. If you lift the clear pot out of your decorative pot, you can check on the health of the rest of the roots by looking at them through the plastic.

As there are at least a couple good roots, your orchid has a chance of recovery but will need some good care.

How do you water? How do you know when to water? You should be lifting the inner pot out of the decorative pot and checking to see if the bark has any moisture in it. If you can't see any, water by soaking the plant, pot and all, in a bowl of water for 5 minutes. Then let it drain thoroughly and replace it in the decorative pot.

Your orchid will bloom again but, to accomplish that, it will have to be healthy.

I like the videos here for really showing you what you need to know
https://www.youtube.com/user/M...

Thank you so much for your advice BigBill, Will C, DaisyL and sallyg. I really do appreciate it. I am trying to tend to it by using the watering method advised here. A few more queries please while I try to understand my Phal better...

It's quite hot these days in the UK, and within one day the moisture seems to disappear from the bark. Should I be watering 2/3 times a week while I am trying to revive it, with the potting mix as is?

I plan to repot the Phal with the right potting mix, as advised. Can I repot the Phal while I'm trying to bring it back to health? Should I snip off the withered roots when I repot?

Wrt an apt position for my Phal, I don't have a North facing window in the house. Would a North-East window work or is that too intense? Also, the flower spike has turned completely brown and dry. Is that ok?

Thank you so much in advance!

A little morning sun won't hurt it!

A great thing about Phalaenopsis is that they respond well when repotted! Once yours is in the proper mix, within 4-6 weeks, you will see new root development. With new roots the leaves will hydrate and get firmer. New leaf production will start. But you must repot as soon as you can. The longer you delay, the longer the recovery will take but I am confident that the plant will look a whole lot better a year from now and it will bloom quite probably after the new year. Good luck and please keep us updated.
Just don't use too big of a pot!

Thanks BigBill, will repot it right away! Was planning to reuse its current pot. Should I get one slightly bigger?

When you take it out of the pot, trim and discard all dead roots. The live roots will be obvious, round and firm. Use pot appropriate for the root mass.
If it is a four inch pot, try watering every four days, 5" pot, 5 days. With smaller sized media it will recover quickly.
I have every confidence that you will message us when it recovers and blooms again!!