i've figured different methods working to resolve the issue of "cannot move (drag) folders or files on desktop".
solution1: delete 3 files from /Library/Preferences and reboot.
(com.apple.desktop.plist, com.apple.finder.plist, com.apple.sidebarlists.plist). To do that, open any finder window, then press "alt" and "Go" on menubar on the top. You will see Library. Go there and find Preference folder. Delete. Reboot.
solution2: create "tmp" folder in root directory of your logical volume if missing. Reboot
-your root directory is basically c:\ (whatever is your primary partition)
-please check if the "tmp" shortcut is already there (to do that, open terminal and past this
defaults write com.apple.finder AppleShowAllFiles YES) then navigate to c:\
-if the tmp is not there, create and reboot.
-if the tmp is there as a shortcut or folder, don't mess around.
solution3: "release" the desktop.
-goto terminal, type sude chflags -R nouchg
-drag and drop your "Dekstop" folder. (if you can't find yr desktop folder, click anywhere on desktop, click "Go" and choose "Enclosing folder"
solution4: remove ".DS_Store" invisible file from desktop.
-open terminal and paste defaults write com.apple.finder AppleShowAllFiles YES
-try to delete .DS_Store file (not always possible)
as for me, solution No.3 worked fine. rest did not work out.