Not ready to delete your working Windows for a custom build? You do not have to. Dual boot lets Moon OS live beside your current system while you judge it with real use.
Dual boot is the grown-up way to test an unofficial OS: your current Windows stays exactly as it is, and Moon OS gets its own corner of the disk. Every startup, you choose which one to use. If Moon OS disappoints, you delete its partition and your life continues untouched. The method below assumes one PC with one disk that has free space to spare - read each step fully before starting, because partition work punishes hurry.
Illustration: the layout this method creates. Your sizes will differ; the shape is the point.
Back up your important files first - partition changes are routine, but routine is not a promise. Then open Disk Management (diskmgmt.msc), right-click your C: drive and choose Shrink Volume. Shrink by at least 40 GB to create unallocated space for Moon OS. Leave that space unallocated - do not format it, the installer will handle it.
diskmgmt.msc, press EnterBoot from the Moon OS USB and choose the custom install. On the drive screen, select ONLY the unallocated space you created, and let setup use it. This is the one moment that matters in the whole process: your existing Windows partitions must stay untouched. If the screen confuses you, stop, restart into your normal Windows, and re-read - your system is still fully intact at this point, and patience is free.
A correct install leaves a boot menu: each time the PC starts, you pick Moon OS or your original Windows. A few honest expectations: Moon OS may set itself as the default - you can change the default and the waiting time later in System Configuration (msconfig) under the Boot tab. Clock note: dual-boot Windows systems occasionally show the wrong time in one OS after switching - a small, known quirk of how Windows stores the hardware clock, fixable and harmless. And keep your files that matter in one place you back up, not scattered across both systems.
Leaving is clean when it is done in the right order. Boot into your ORIGINAL Windows, open Disk Management, delete the Moon OS partition, then extend C: back into the freed space. If the boot menu still lists Moon OS afterwards, open msconfig, go to the Boot tab, and delete the Moon OS entry - leaving your original Windows as the only, default entry. Restart twice to be sure everything is back to a one-Windows life.
See the full download, install and first-look walkthrough on screen, step by step, in the video.
Watch Full VideoNo. The two systems never run at the same time and yours is not modified. Moon OS only costs you the disk space you gave its partition.
40 GB is a workable minimum for the system plus a few apps. If you plan to keep files and more software inside Moon OS, 60 GB or more is more comfortable.
Yes. Delete its partition from inside your original Windows, extend C: into the space, and remove its entry from the boot list in msconfig. Your original Windows never gets reinstalled or touched.