GemLuva, I would like to clarify something, not only for you, but for other forum users too.
When I reach for help in a forum, I hope to find someone who knows enough to point me in the correct direction, and that will take the time to explain, without "assuming" that I already know almost as much as he does.
When such a user posts, he can't know beforehand how much I already know. He may assume that I know things that I actually don't know, hence leaving me not really understanding. OTOH, he can "over-explain", making the post too long and too basic for
me.
From what I read in your first post (2 first posts actually), I couldn't know beforehand what is your specific level of knowledge. In addition, other users reading this topic may take advantage of posted details, that you specifically already know.
Please keep this comments in mind for the future, in this or at any forum. I don't think that someone takes the time to help, but he has some other "hidden upsetting goals" in mind. In any case, please accept my apologies. By no means my intention was to sound condescending (I wouldn't really know how to sound like that, if I would ever wanted to, since English is not my birth language).
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Anyway, about Nero. AFAIK, all versions of Nero have the possibility to open a previously saved "project". Depending on the specific version of Nero, opening an ISO image can be done in several
different ways (as you mentioned). The tutorial I linked to is the more "general" one so to cover most of Nero editions and versions. The "bigger" editions will still include the more basic characteristics.
The important feature to distinguish here is that
opening an ISO image (for burning it or editing it) is not the same as starting/building a
new "Data" disk / job / task / project, and is neither the same as starting/building a
new "bootable" disk / job / task / project.
If you download UBCD, PartedMagic or any ISO image for that matter, you should burn the optical media "as an ISO image". In general, the ISO image should already contain the "bootable" part (if it is a bootable CD/DVD).
The option you chose from Nero (or tools alike), "make a bootable disk", is not dedicated to burn an ISO image that you download. That option is for "building" a
new ISO image (or directly burning a new optical media) that you want it to have the "bootable" characteristic in addition to whichever general data you were adding.
That's why you didn't see the files and folders in Windows Explorer before. As explained at
http://www.ultimatebootcd.com/download.html, after burning the UBCD optical media, you should see a folder tree at least
similar to the one shown in the download page.
If, in Windows Explorer, you select to display hidden files, and you don't see any file/folder, or you only see 1 ISO file (as explained in the download page) burned in the CD/DVD, then the burning job was not done as it should.
Let us know if you have more questions about UBCD or PartedMagic.