Function of で in these lyrics

Question

I've been trying to self-translate the lyrics for Secret Base, and this line somehow confuses me.

突然の 転校で どうしようもなく

What exactly is the use of the で here? And what is its translation?

Answer 1

で here functions like "due to".

Answer 2

Let's try to break the sentence into parts.

突然 can be called a の-adjective (more on that here). There are myriad connections that の can perform (not just the usual possessive one). If you're interested in all the possible meanings of の, I recommend checking the book A Dictionary of Basic Japanese Grammar.

転校 is a name, which is being qualified by 突然. All in all, the group 突然の転校 is a name, meaning "sudden change of school".

どうしようもなく comes from どうしようもない, which means "there's nothing that can be done about it". ない is an adjective, and although the く form normally changes the adjective into an adverb, it can also be used to connect sentences (more on this here), similar to the て form.
As a side note, the stem of a verb can also be used to connect sentences.

From here, it's easier to grasp the meaning of で: it's connecting the two sentences. For nouns and な adjectives, you used で for connections such as 賑やかで大きな町 (a lively and big town).

Summarising, the sentence means

There's nothing I can do about the sudden change of schools. (lit. there's a sudden change of schools and there is nothing to be done about it)

Edit:

The previous example connected two な adjectives, but it can be equally used to connect sentences/ideas (as is the case in the OP sentence). Here's a better example, taken from a college website:

やましたせんせいはにほんじんで、よんじゅっさいぐらいです。