I installed PC Health Checker to see whether Windows 11 can run on my computer, but sadly, it told me my PC was not compatible. Then, I heard that Windows Media Creation Tool can help me get Windows 11 installed on my incompatible PC. Indeed, I succeeded.
I once reinstalled my Windows OS with Windows media creation tool. It's totally free and you can get it from Microsoft official website. Please note that make a backup of your important data in case of any accident during reinstalling.
I suggest you test your hard drive speed at first: Step 1: Right click Task Bar on the bottom of your screen, and choose "Task Manager" in the extended menu. Step 2: In the pop out windows, you will see different tabs on the top, click "Performance". Step 3: Choose the hard drive on the left...
It seems that you cannot delete it directly, you can use the free space to create a new partition by "New Simple Volume" or extend a partition by "Extend Volume" in Disk Management.