DISCLAIMER:
+ Editing Registry can render your Windows unstable. You can lose all your data.
+ Windows System Restore (creating a Restore Point) may not be able to help you, for two reasons: conflict with cloud software AND nowadays the hard disk is locked by Bitlocker.
– Now, there are basically FIVE Steps:
1. Back up every thing important to you to a cloud software or USB key.
2. You should be logged in from an Admin account OTHER than the account whose username you want to change. Please have atleast two admin accounts for yourself on your computer, one of these should be a local admin user (I demonstrate how to create one).
Following three steps have to be done during ONE session:
3. In Search, type Run; then press ENTER, then type netplwiz. Change the concerned account’s username under Properties.
4. Rename the Folder under C:\Users, I mean the username you do not like. it should match step two.
5. In Search, type Run; then press ENTER, then type regedit. Back up the Registry before editing it, by Exporting it. Now, edit the following Registry key after locating it exactly.