virtualbox.org

In order to register for this forum, I had to pick a version of VirtualBox. The choices were all OS* where one of them was OS - Other (so that's the one I chose). I'm sure I'm wrong since I'm using a W7 Host - but could not figure out what that field meant. Perhaps one of you could set me straight? Thanks.......

It is more than likely the PUEL one you want.

What is PUEL and what do the others mean? I couldn't find any reference in the About section of VirtualBox - or anywhere else I lokked.

Well that's a long story. In the beginning there was PUEL or personal use edition license and OSE open source edition.
The others are specific builds. Since you are using Windows and probably did not compile it yourself the it would be the (now defunct name) PUEL. Oracle decided to completely remove the closed source from the code and made it available as an Extension Pack.

OK, thanks. Now, since I'm using VB 4.1.2, should I go ahead and install Oracle's extension pack 4.1.2? Are there other extension packs available? If so, where can I find them and what do they do? (Or, for now, should I just not get into extensions?)

The ExtPack is all the extra you need. The guest additions for the guest are included in the main program.
You also have a manual that you should read to become familiar with the product. press F1 when you open the main manager or click help -> contents.

I printed the manual - but it's about 200 pages long and gets too technical for me (unfortunately). Still, I DID read what I could understand. The extension pack has a warning on it when you try to install it. So, I aborted the installation until someone knowledgable can tell me why I shouldn't (or should) install it (since I don't understand what it's for).

From what you say you want to do you need it.
I don't recall seeing any warning though.

Only warning I can think of is the license agreement for the extpack, which is the PUEL license.

Thank you! What are PMs? I don't ever plan to use Linux. Should I still read what you suggested having to do with Linux?

PM = Private messages. See under your information at the right.
You don't need to read Linux specific information if it does not pertain to you. However it never hurts to learn something new.

Thanks!! Learning VB is new for me.