Hello
The HP Stream comes with a very small built-in drive, which quickly fills up with updates and files. This makes resetting difficult, since the process requires free space on the C: drive for reinstalling Windows. I believe it is for such limitation, many HP Stream models have been discontinued.
Anyway, what you need is a clean install. The key difference between factory reset and clean install is - factory reset is initiated from existing Windows system, hence it needs enough system drive free space for Windows to start this process. Clean install is initiated from a installation media (typically flash drive) that contains Windows installation files, so it bypasses the current Windows completely to install new Windows into the disk.
To perform a clean installation of Windows 10 using the Windows Media Creation Tool. You do need to get access to another computer so you can download the Windows installation files into a flash drive, then use the flash drive to help your computer. If your current computer is running low on space, I fear you definitely need another computer to help you do this process first. Hopefully you have a spare computer, or you can have friend or family help you.
The following steps should be done on a working Windows computer:
Download the Windows Media Creation Tool from Microsoft's official website. https://www.microsoft.com/software-download/windows10
Run the tool and select "Create installation media for another PC."
Choose your language, edition, and architecture (32 or 64-bit) and select "Next."
Choose "USB flash drive" as the media to use for the installation and select "Next."
Connect a USB flash drive with at least 8 GB of free space to your computer.
Select the USB flash drive you want to use, and then select "Next."
The tool will then download the required files and create the installation media.
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Now these steps will be done on your problematic computer:
Go to the computer's BIOS boot menu to have it boot from the USB drive.
Follow the on-screen instructions to install Windows 10, making sure to choose "Custom install" and select the option to delete all existing partitions.
Once the installation is complete, you'll have a clean installation of Windows 10 on your computer.