How can I change the default opening folder when i right
click on start menu an dthen explore
You can't. The start button is a graphical representation of the start menu
folder, so choosing Explore in this location will alway open Explorer to
those folders.
Instead create a new shortcut for Explorer. Go into its properties and add
the target line that you want (see below). Drop this shortcut into your
Quick Launch toolbar for quick access.
I keep an Explorer shortcut in QL with this target:
%windir%\explorer.exe /e,
It opens Windows Explorer with the focus on My Computer. Alternatively, the
target line: %windir%\explorer.exe /e,c:
would open Windows Explorer with the focus on C: