How can you list registry valuenames for a given keyname?

I tried the following to attempt to list all the valuenames under "Run" 
but it doesn't work:

MsgBox(4096, "Startup Items Are:", RegRead
("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion", "Run"))

If it can't be done, is there a commandline way of exporting a registry 
branch using, say, Regedit please?