My current windows 10 installation is too bogged down to play games properly. I've tried all the traditional solutions to speed up my PC but none of them made any noticeable difference, so I'd like to try a fresh OS. I'd prefer to avoid doing a "Reset My PC" option and having to re-install all my apps. So I'm trying to install a second windows 10 onto a new partition that will just be used for playing a couple games.

The media creation tool USB option doesn't work on my pc. The USB gets ignored when I boot normally. If I try to boot it directly from the boot menu, I get a "selected device failed to boot" error (with both windows 10 and windows 8 media creation tools). I used a brand new USB drive and tried it immediately after installing the tool onto it. I also tried re-installing the tool a second time.

I tried running the setup.exe at the root of the USB drive, which started properly. However, all the guides I've looked at say that I should get a "custom install" option when running this tool. This is where I would have the option of selecting the partition I want to install windows to. I don't get that option. It just asks me for the basic language/architecture fields, then gives me the "keep everything/keep files/remove everything" options. There are no options after that. If i I click install, the installation begins.

I tried using the windows 8 setup.exe on the USB, but it asks me for a product key. My computer came with windows 8, but I don't have the product key anymore.

Is there any way to get a fresh windows installation without having to overwrite my current OS?