How to solve the disk problem?

Question

Hard disks

After reinstalling Windows 10, there was such a problem with the disks that the D disk became the main one, where the main OS files are stored, and the C disk took over its old role. (And they also changed partitions)
Actually, I need the main files to be stored on the disk where less memory. Is there any way to change this?

Answer 1

You can, of course, unmount the data drive (not the system drive), and then change the letter of the system drive (you may need to restart the computer), BUT the consequences for the system and software can be deplorable, because you never know where the system drive managed to register under a different letter

Answer 2

when installing the system, select the correct disk \ partition for installation ... otherwise nothing

Answer 3

This is the same hemorrhoids with backup to an external drive. In short, take an external drive, make a backup copy on it using Windows, then overwrite the system drive with a boot drive, transfer data from the information drive to it, overwrite the information drive and deploy a backup copy to it.
The process is described in more detail here .
But this is a very, very crutch solution. You shouldn't have fun like that without a very important reason.