There is a backup folder in drive D, which is a favorites folder. How can I delete it or...

If you want to change the path of my documents and favorites to drive C, we recommend that you change it to the default path of the original system.

How to change my document to drive C is as follows:
Right-click my documents on the desktop and change the content behind the "target folder" to c: \ Documents ents and Settings \ Administrator \ My Documents ENTs.
Note administrator can be changed to your current user name

To change the IE favorites, follow these steps:
Start ---- run the input regedit
Find
HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Explorer \ User Shell Folders

Change the value of favorites in the right sidebar to c: \ Documents and Settings \ Administrator \ favorites.