What you ask is nonsensical. You've clicked the Start menu's context menu. It is only going to have commands related to the Start button. If you want My Computer you r/c My Computer.
The Start Menu is built from folders. Therefore the Open and Explore commands are the Open and Explorer commands on all file folders. Change one and they all change.
To change it.
Type in Start Run
regedit
Navigate to
HKEY_CLASSES_ROOT\Folder\shell\explore\command
and change it to EXPLORER.EXE /e,::{20D04FE0-3AEA-1069-A2D8-08002B30309D}
EVERY FOLDER WILL NOW EXPLORE TO MY COMPUTER
To add an extra verb to folders
Go to
HKEY_CLASSES_ROOT\Folder\shell
and right click the key - New Key - Give it a name (Explore My Comp). Select this key and create a new subkey called command. Double click the default value in the right hand side pane and add the same as above.
You really should access these groups correctly. Then I would have attached a small file to make the changes (but you can't see it cos you access here the idiots way). Click here for the correct way to access news://msnews.microsoft.com/microsoft.public.windowsxp.customize