When it is at the beginning of a sentence, or at the end of a letter. I don't see it capitalized anywhere else.
No, because it is n ot a proper n ou n.
As you have stated it, that is not entirely correct. If it was a single sentence then the word "thank" would not be capitalized, and if it is two sentences, then there should be a period after "assessment". You might find it more economical to say "Thank you for the assessment."
Yes, "PC" should be capitalized in a sentence.
No, the word forecast should not be capitalized in a sentence.
Yes it should be capitalized.
No, "secondary students" should not be capitalized in the middle of a sentence unless it is a proper noun or at the beginning of a sentence.
No, the word "fifteen" should not be capitalized in a date within a sentence unless it is the first word of the sentence.
Always. If you don't you are making a Grammar mistake.
Since "transition process" is made up of common nouns, it should generally not be capitalized in sentences. It should only be capitalized when it starts a sentence or appears in a proper name or title.
Have should be capitalized if it is the beginning of a sentence. Summer should not be capitalized.
Since 'felon' is a common noun, it is only capitalized if it is at the start of a sentence.
No, "methamphetamine" should not be capitalized unless it is at the beginning of a sentence.