Continuing the topic of obscure OS-tan media, there is quite a bit of unknown official pieces of Microsoft OS-tan games, manga, and more that is now lost. This post, of course, will not be discussing unofficial/doujin OS-tan lost media as it is way too wide of a collection (However, there may be a post about some highlights of favorite overall Japanese unofficial/doujin lost media someday).

First of all, let's cover the lost Nanami Madobe game: Nanami Madobe's Heart Crisis (窓辺ななみ ハート クライシス). 

The game was a "card choice" game where the player would have to choose the correct attack cards to deal with various computerized enemies. Apparently, there was also a card that showed Nanami's parents in the game; we're missing out on some important lore. This information is based off of simple descriptions of the game from Japanese player HAGER and player Crystalyn from Anime News Network since there are sadly no gameplay images or videos online showing it off. Luckily, we do at least have images of enemy-transition screens and wallpapers awarded for beating the game thanks to Chinese player CCSX.

Next up is the OS-tan manga: Attack on Madobe Family / Comiket Raid (進撃の窓辺ファミリーコミケ急襲作戦).

(Image courtesy of Suruga-ya)

This was a manga that Toshiya Takahashi illustrated and Microsoft exclusively sold at Comiket 87 along with many other OS-tan items, including special OS-tan DSP releases of Windows 8, badges, Touch Mice, bags, and more. The manga revolves around the Madobes' experiences in Comiket, with Nanami and Claudia showing Yuu and Ai around and introducing them to the event. Of course, this summary comes from Shimogawa's review as the full manga is lost.

Finally is the (partially) lost Internet-Explorer-tan OneDrive, including downloadables such as a specially-themed Internet Explorer installer (which was also lost until I found a download), various images of the character at conventions, fan-made MMD models, and custom Windows sound schemes. A lot of the goodies are present in https://archive.org/details/inori-aizawa-onedrive and https://archive.org/details/inori-aizawa-ie11-win7-setup-1.0, but some downloadables, such as the aforementioned convention images, are not included and currently lost to time.

Missing downloadables info courtesy of Jake Smith in a comment on the latest post of https://www.facebook.com/InternetExplorerTan (fan account; official account was moved to https://www.facebook.com/InoriAizawaFans which is now also a dead link :()

Overall, official OS-tan media is quite a bit more extensive than I initially thought, with some such as these being quite obscure. If I receive any updates on these pieces, I'll be sure to update this post, and if I find some more notable entries... maybe make another blog post, like what happened with the Touhou and Seihou trials. O_o