Sick Orchid- really need help. Thank you.

Orchids should be repotted every two years. The reason is that the potting medium breaks down and compacts. This causes the roots to remain wet longer than is good and can lead to rot. Rotted roots turn gray or black. The green stems at the base are probably new roots. They can turn white if they remain dry for long but this doesn't hurt them. As soon as they find their way into new potting medium they will turn green.

Choose a pot with good drainage. You can drill extra holes into a plastic pot to increase drainage and get air to the roots. Make sure the new pot can hold the roots, but don't make it bigger than it has to be. Select a well draining media to replace the media in your current pot. Course fir bark and coconut fiber is a good combination. but different orchid species may do better with other types of media. Below are parts 1 and 2 of a video on repotting a phalaenopsis orchid. If you have another species look for specific videos on repotting that type.

https://www.youtube.com/watch?time_continue=9&v=v9FN6HBokzU

https://www.youtube.com/watch?time_continue=224&v=uiZB7SW5H-Y

Those are air roots at the base of the orchid... since most orchids sold in stores are originally from Central and South America and are tree dwellers, those function to grab moisture from the air in the forest canopy..... here is info how to care for them.... https://www.justaddiceorchids.com/orchid-health-and-anatomy

Buy Orchid Compost and follow instructions to re-pot.

https://www.gardeningknowhow.com/ornamental/flowers/orchids/repotting-orchid-plants.htm