Typing "reg" and not finding regedit is a symptom of Windows 7's search--it won't find an item based on 3 or fewer characters unless you have found it once already. After you type "regedit" and run, the next time you type "reg", it should find regedit.exe.
The quick answer, you're pretty much there. Check value of Current in the key HKEY_LOCAL_MACHINE\SYSTEM\Select. This will tell you which of the CurrentControlSet00X's you need to make your change in.
For example, if Current is set to 2, you need to edit HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet002 with your changes.
The way it works is this:
Windows always keeps a few copies of this key, suffixed 001 to 003 (only 2 in Windows 7 I think?). CurrentControlSet001, CurrentControlSet002 and CurrentControlSet003. Think of them as the master keys that are persistent while the computer is switched off.
When you log into Windows, it picks the last used key, using the value of Current in the HKEY_LOCAL_MACHINE\SYSTEM\Select key. The content is copied into a key called HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet. This key is what Windows plays with while you are logged on.
When you log off of Windows, changes are written back to the key that was original copied from when you first logged on. CurrentControlSet002 for example. CurrentControlSet vanishes, so to speak. This is why you are unable to see it while you are logged off, working from the recovery console :-)
Probably a bit over the top with my answer (I blame the Red Bull), but I figured I'd answer a detailed question with a detailed answer.
Best Answer
Yes.
You can open another "hive" with regedit.
However, this will only work on Win2k/Xp/Vista/7, there is no way to load the registry like his in Win9x/ME.