Can I change drive numbers from within windows 10?

The system started with 7 partitions including 2 with letter, the other 5 didn't have letter in Windows. Now, Linux accident apart, it's w/o extra EFI or Recovery partitions, 4 partitions total, 2 with letter.

I cannot see any dvd writer. Does it have to do with (post #1) "I sometimes put a usb extender on this computer which I suspect is causing the problem."? What is an "usb extender"? Do you mean a hub with several drives or USB sticks connected including or not the dvd writer?

I know that if there's only ONE Google Drive it takes the letter G: for itself. If there exists other connected drive with letter G: then Idk what happens (if GoogleDrive behaved/behaves like just other physical drive, it would just be assigned a further letter, but Idk if the premise is true). With 2 or 3 GoogleDrives that could steal letters (if so) to connected drives or among them, Idk what can happen. Idk if 2 or more GoogleDrives are supported and what are the letters rules in this case. Idk either why the letters E: and F: aren't being used (if they are free, the normal Windows behaviour with normal drives would be assigning them).

In post #6:

Do you know what is GOOGLEDRIVEFS (G:)?
Aren't there 3 Google drives counting G: H: and J:? (I see G: has normal drive icon, not Google's, but Idk what does it mean, letters messes apart).

Read Megahertz' post 72 link to the standard remedy to assign a given letter to a Google Drive. The usual remedy for reserving concrete letters for concrete drives is choosing letters far enough in the alphabet like P: (I'm not meaning P: is a priviledged letter to avoid problems, N: V: S: etc would serve the same if you never connect enough drives to reach there).

JLArranz said:

I cannot see any dvd writer. Does it have to do with (post #1) "I sometimes put a usb extender on this computer which I suspect is causing the problem."? What is an "usb extender"? Do you mean a hub with several drives or USB sticks connected including or not the dvd writer?

There is a port extender like this one.

If I plug a usb memory stick in it usually calls it e: or e: & f: if I plug two in.
Sometimes I plug a card reader in like this one

It has a number of slots for memory cards, you can see a card sticking out of the top right corner. It allocates drive letters for each of the ports, so now it is plugged in I see E:, I:, L: & M: which are the slots in the card reader.
E; is the card that is plugged in and I can read it. The others ask for a card to be plugged in if I click on them.

I am assuming this could cause a problem with the google drives changing, there are 2 google drives and a cloud drive (that usually stays on P:).
(GOOGLEFS(G:) sometimes shows and, as this example, sometimes fails to show?)

JLArranz said:

Do you know what is GOOGLEDRIVEFS (G:)?

No it says it can't find it if I click on it when it is there?
Sometimes the google drive on J: shows up as H: and that is my problem. I would like it to either stay on H: or J:.

Card readers can have different behaviours with the letters. I've two, both internal, USB connected (to internal USB connectors) and in different computers. One is very ancient, it's USB2, it belongs to a floppy reader/card reader combo, and occupies two letters permanently (plus A:\ for the floppy) because its two drives are fixed, even if it doesn't have any card inserted. These drives act like an internal floppy reader or optical drive with reserved letter. The other is a modern USB3 one, that can use up to 4 or 5 letters but only if it has cards inserted, because their drives are removeable. I'm in the latter computer now. If I insert a new card or new USB stick it gets the letter H:, first free one for removeable drives, unless other drive has caught it, in which case it would catch the following available one (I: or a further one). Windows remembers the last letter used for every drive and assigns it unless it's in use, in which case it assigns the first available one.

I'd use the solution linked in post #72 to assign your Google drives far enough letters, for instance R: and S:. I'd leave alone GOOGLEDRIVEFS (G:) at the moment, but Q: would be a good letter for it if you ever need to change it.