Install windows instead of ubuntu?

Question

Windows

Good afternoon! Today I installed ubuntu (I decided to try what kind of OS), put it on top of windows 8.1 (that is, the hard drive was completely formatted). I rummaged around in this OS and I didn’t really like it (but it’s great on servers), I wanted to install windows again, but the trouble is that exe files don’t open in linux (I installed wine, it also doesn’t work through it), then I tried to make a disk image - inserted a flash drive (it was already prepared for installing the OS) loaded the ISO image of windows 8.1 onto it (ubuntu has such a contraption through which it loads (well, or I'm a fool)).
Well, after that I reboot the PC, go into the BIOS and put the USB flash drive as a bootable disk (well, I don’t know what to call it), I reboot the PC again and it asks what to download, I chose the USB flash drive and ubuntu still starts ...
What's the matter? Either I'm doing something wrong, or I don't understand anything at all .. Please tell me detailed instructions for installing Windows INSTEAD of Ubuntu ..
Ps Ubuntu 15 is installed

Answer 1

askubuntu.com/questions/289559/how-can-i-create-a-... Follow
this instruction to make a bootable USB flash drive from windows 8.1 iso file
Then boot from the flash drive and install windows.
For the future - to "try" it is better to use virtual machines.