A few months ago, I had Windows 8 as the only operative system on my computer and I wanted to install Ubuntu, having both operative systems on my pc (dual boot). However, after supposedly installing Ubuntu, I wanted both Ubuntu and Windows 8 to appear on the screen when booting (so I could choose which one I wanted to work with), and that's when the problem appeared... in the terminal, I followed a tutorial that could make the dual boot work (I don't remember what I wrote) and, all of a sudden, all of my partitions were gone. I initiated the computer again and it would go straight to the BIOS. Then, after several tries, I somehow installed Ubuntu and have been working on it since. However, I know that all of my partitions are messed up and now that I need both Windows and Ubuntu on my pc, I want to delete the current Ubuntu that I have and start working on the computer like it didn't have any operative systems (install both Windows and Ubuntu from scratch). I really appreciate any help that you can give.
I attached a print screen of gparted, which shows all of the partitions on the computer.