The tag 'septimus signus' on WindowsForum.com is associated with a single thread titled 'Septimus Searches for an Elder Scroll - Skyrim Prank Call,' which contains a YouTube video link. This tag appears to reference a character from the video game The Elder Scrolls V: Skyrim, specifically Septimus Signus, a reclusive mage involved in a quest for an Elder Scroll. The content is humorous in nature, presented as a prank call. No other topics such as Windows, hardware, or IT support are covered under this tag.