Windows 10 clean install and hard drive partition

Reset

Since you have already upgraded to Windows 10, you can effectively get a clean install by resetting. If you want a real clean install, you can always just create an ISO using the Windows 10 media creation tool.

First go to Settings and then Update & security.

Then on the left side click Recovery.

Under Reset this PC select Get Started.

In order to do a full reset you'll want to select Remove everything.

Partitions

Disk Management is the same as it was before. There are a few ways to get there. The way I usually do it is open Windows Explorer and right click This PC on the left. Then select Manage.

Once Computer Management opens, select Disk Management on the left.

Here you can partition drives, shrink volumes, etc.

I figured out what needs to be done in the situation I had posted:

1. If you have an official version Windows 7/ Windows 8, you are entitled to a free official version of Windows 10 until July 29, 2016.

   If you want the official version, you must upgrade via the upgrade provided by Windows. This will not be a clean installation but will be an install nevertheless. Your device will be registered with Windows as official for Windows 10.

   If you want a clean install, skip to point 3.

2. If you want to do a clean install, you can easily do it after completing step 1. All you need to do is ensure that your computer has been registered with windows 10 and then you are good to go for a clean installation.

3. Download the Windows 10 Media Creation Tool. It asks you if you wish to install or create installation media. I created installation media on a 4GB pen drive.

   Then I downloaded Windows 10 again. I believe you could copy (I didn't try it so don't know how it works, but if downloading isn't going to be big issue for you, you could do it again).

   Then I restarted my PC in bootloader mode while keeping my pendrive attached. Then I had to change my boot order for me to be able to use my pen-drive as an installation media.

   It is very easy to perform a clean installation after that. Just walk through the steps. Selecting the option "Nothing" will help you do a clean install.

   You could look up ThioJoeTech's video on "Windows 10: How to Clean Install with Upgrade" for all steps for Media Creation Tool as well as clean installation.

   You could look up this video for changing your boot order.

4. The partition part, I believe, works same as on other versions.

5. The lags are still there, but with updates, they are reducing. So I believe I need to give it time.