I wanted to buy a laptop, but I saw that it is only available with DOS. Can I just play Windows? Do I have to buy a license + CD? Or USB stick?
If a laptop is sold with (MS) DOS, Windows 10 will probably not run at all
FreeDOS is offered on it.
That's nonsense, there are a lot of laptops that are offered cheaper because there's no Windows. This is not because Windows does not run on it, but because the manufacturer wants to save costs with Windows licenses.
You can install and use Windows on any standard laptop with a normal design (i.e. 32/64 bit system).
Laptops that are delivered with FreeDOS are usually cheaper because the manufacturers do not have to provide expensive Windows licenses.
To install you need a license, which costs only 24.99 euro with License King.
License King: https://lizenzking.de/microsoft/windows/windows-10/microsoft-windows-10-home
You can then install Windows with a USB stick that can be created with the Media Creation Tool from Mircosoft.
Media Creation Tool: https://go.microsoft.com/...kId=691209
I have been buying Windows and Microsoft Office licenses for myself and my customers here for years. 100% leagl and serious.
https://www.rakuten.de/produkt/microsoft-windows-10-professional-vollversion-download-1-pc-2591462060
Does the laptop have a hard drive because DOS also runs from an internal chip with 2MB.
You can easily download Windows 10 as an evaluation version from Microsoft or burn it to DVD or build a bootable stick.
https://www.microsoft.com/.../windows10
After the installation you have 90 days or 180 days to buy and enter a license key depending on the version there are license keys from 10 euro (eg on Amazon)
You can also order a full version with DVD and "manual" on Amazon from 30 euro
Windows 10 runs on everything possible somehow even on 486DX computers but if you have special hardware and drivers you have a problem. For example, Win 10 still runs with 8Bit ISA Soundblaster cards and PCI graphics cards but not with exotic hardware.