Microsoft® Manual of Style, Fourth Edition

Semicolons

A semicolon between two independent clauses indicates less of a pause than a period. If the clauses are not joined by a conjunction, use a semicolon. Otherwise, use a comma before the conjunction. Semicolons are useful in joining two contrasting statements.

Use semicolons sparingly. They are difficult to see on low-resolution monitors.

Use semicolons within a sentence to separate phrases that contain other internal punctuation, especially commas. This practice is most common in making brief lists. Such sentences, if they include more than three elements, are often easier to read if you break them into separate sentences or use the elements to create an unordered list. For example, the following sentence is difficult to read:

In this tutorial, ...