"Looping"

I have to write a script that will append a value into the registery for each entry under a set key.  The number of entires can vary from system to system it can be as little as 2 or as many as 50.

Is there some way to loop through a key like this?

Example:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}
\0000\Speed
\0001\Speed
\0002\Speed
....
\00??\Speed