Can you create a computer running 100% gnu software?

Not just free software, mind you. Hell, not even just software backed by the FSF. It HAS to be a gnu project. While that already leaves a fuzzy definition, trust me, it gets even less defined.

A hypothetical full gnu system would be booted using GNU Boot. It would use GRUB (not a big surprise, it's already a defacto linux standard) However what it boots into is the first true challenge. See, Linux isn't a GNU project (Hence the recommended term GNU/Linux. See this and this). Linux is a kernel, a necessary thing for a full OS to run. Luckily, GNU Has it's own kernel, GNU Hurd! Unfortunately, because linux exists its development has slowed to a crawl. For now, we'll put a pin in this. Next up is what most people would see as an OS, the distro. GNU/Hurd distros are already hard to come by, let alone one that is actively maintained as a GNU project. However, there may just be a solution. GNU Guix is GNUs own package manager/linux distro. By default it uses the FSF recommended linux-libre, however it has a VM image of it running GNU Hurd. If someone could run this on real hardware, wed have a GNU maintained GNU/Hurd distro. Next is the DE. In case you didn't know, GNOME started as a GNU project. Despite soured relations, older GNOME versions were still actively GNU projects so an old GNOME version should work well enough. After this, you basically have a full system and anything else you could need has a gnu alternative (They even have their own damn internet)