Learn Russian: Компьютер работает, а информации нет. - The computer is working, but there is no information.

The word нет (meaning "there is not" or "there is no") always forces the "missing" noun into the Genitive case. In Russian, whenever you want to express the absence or lack of something, that thing must take a Genitive ending.

How exactly does the ending of информация change to make it Genitive?

Most feminine nouns ending in -а or -я change their ending to -ы or -и in the Genitive case. However, words ending in -ия (like информация) are a bit special: the final -я changes to -и, resulting in a double -ии ending (информации).

Why does the English translation say "but" when the Russian word is а? Shouldn't "but" be но?

Russian has two common words translated as "but": но and а. We use а here because we are simply contrasting two different subjects (the computer vs. the information). но is generally used when the second half of the sentence contradicts an expectation set by the first half.

If I wanted to say "it is not there" instead of "there is no information", how would I use the pronouns from this lesson?