Orchids dying, why?

[CAHCO81]

Hi all,
Ok so I posted a few weeks back (original post is below) about my phal dropping blooms and another phal I have. But with in the last week my larger phal has dropped all it's blooms and has a wilted yellow leave, not the bottom one but right above it. I am not certain if this is just it's normal cycle or if it is very sick. I have been trying to water when it looks like it needs it, when the roots dry a bit or when the bark is dried. It is sitting in an east facing window with shaded light but not direct light. If this is just part of it's life cycle should I cut the spikes back if it is sick, please what should I do?
I am posting some new pics of the larger phal, also there is a weird spot on one of the leaves, can you tell what it is.


(Original post)Hello,
I am a new Orchid owner and I got my first Orchid, a moth orchid about three months ago from a florist. It started dropping blooms about a week after I got it. At first I noticed these little white fuzzt bugs on it. I killed every one I could. Then after dropping more blooms I decieded to look at it's roots. They were not good, rotting or dead. It was the bedding it was in, the roots where packed in moss and too moist. I trimmed the dead or dying roots and repotted it in appropriate bedding. It continued to die and as a last resort to try and save it I trimmed both stalks down one more then the other. Now it is starting to sprout new roots and even a new leaf. However the white bugs where back with a vengence. I killed all of them with out thinking to take a picture to show you all. If there are any suggestions on what I can do, they are more then welcome. Secondly I got my second Orchid, also a Moth Orchid about two months ago. Until a week ago it was doing good. But on one stalk it has dropped all it's blooms and is "wilting". I read on line not to re-pot while in bloom but I don't want it to die. I will try and attach some pictures. Please I am loving my Orchids and I don't want to lose them.
Thank you,
Carrie.