Learn Arabic (Modern Standard): توقف الحاسوب لأنه بدون اتصال. - The computer stopped because it is without a connection.

لأنه is made of two parts: the word لأنَّ (because) and the attached pronoun ـهُ (him/it). In Arabic, when you say "because" followed by a pronoun, the pronoun must attach directly to لأنَّ. We use ـهُ here because "the computer" (الحاسوب) is a masculine word.

Why does the sentence start with the verb توقف (stopped)?

In Arabic, it is very common to start a sentence with the verb rather than the subject. This is called a verbal sentence. So instead of saying "The computer stopped" (Subject-Verb), Arabic naturally says "Stopped the computer" (توقف الحاسوب).

How does the word بدون (without) work with اتصال (connection)?

بدون acts as a preposition in Arabic, and it is followed directly by the noun. Notice that اتصال translates to "a connection" because Arabic does not have words for "a" or "an". Simply leaving off the word for "the" (الـ) tells us it is indefinite.

If the computer were a feminine word, how would this sentence change?

You would have to change two things to match the feminine gender. First, the verb would need a feminine ending: توقفت (tawaqqafat). Second, the attached pronoun on "because" would change to the feminine ـها (-ha), making it لأنها (li'annaha).