Windows 10 works with either BIOS/Legacy installation or UEFI, it doesn't matter how you wish to do it given the hardware's setup. If it's got Windows 7 on it already, more than likely Windows 7 will have been installed with BIOS/Legacy mode but can be installed with UEFI mode (I just did that yesterday on a ThinkPad T420s actually for testing purposes) and you still end up in the same. A USB stick/flash drive. Official guide from Ubuntu website says at least 4GB.
FreeDOS 1.3 RC4
The new FreeDOS release candidate is now available! We've been working hard on the next FreeDOS distribution, and we'd like your help testing this new release candidate. The main goals for 1.3 Release Candidate 4 ('RC4') are to provide overall improvements compared to 1.2. Some of these include a LiveCD, a Floppy Edition, new packages, updated packages, and many improvements to the installer to provide hardware compatibility and multi-language support.
How to install FreeDOS | Verify your downloaded files | What's included | Read the Readme file
Windows 10 keeps the Fast Startup feature as Windows 8.Due to this reason, you CANNOT press F2 to enter the BIOS configuration when booting the system.You. Then do the following steps in order: – First, download your Windows 10 which is in the form of an iso file through this link. Then download and run the Rufus software via this link. – By running the program and selecting the downloaded iso file, finally selecting the START flash option will boot. This process will take some time.
FreeDOS 1.3 RC4 LiveCD
The FreeDOS 1.3 RC4 installer. Most users should use this image to install FreeDOS. Depending on your computer system and hardware configuration, you can also use the LiveCD to boot and run FreeDOS directly from the CD-ROM without installation to your hard drive.
FreeDOS 1.3 RC4 LegacyCD
A bootable CD image designed for older hardware. If you cannot boot the LiveCD to install FreeDOS, try this disc image. This disc image uses the older El Torito boot CD format. Some newer computers and virtual machines cannot use this older format. Unless you have a computer that requires this type of bootable CD, we recommend using the LiveCD instead.
FreeDOS 1.3 RC4 Floppy
Basic FreeDOS installation boot floppy image. If your computer has a CD-ROM drive, but you cannot boot from the install CD. Use this diskette image to boot the system. Then insert the install CD. The FreeDOS installer should do the rest.
FreeDOS 1.3 RC4 BonusCD
A non-bootable CD image that contains some FreeDOS packages that are not installed as part of either the LiveCD or the Legacy CD.
FreeDOS 1.3 RC4 LiteUSB
A minimal FreeDOS installer, as a USB fob drive image. This does not contain all of the packages from either the LiveCD or the LegacyCD, and instead only contains a basic set of FreeDOS packages. (Also available as a VMDK file.)
FreeDOS 1.3 RC4 FullUSB
Boot Options Win 10
Plain DOS system and Full install USB stick image. (Also available as a VMDK file.)
Installing Free Win 10 Boots Up Bios Download
How do I write the IMG files?Read this How-to article » [howtogeek.com]