By far the best way to avoid viral infection is the first option which
you suggested. One of the trademarks of a standard virus (meaning a
non-worm) is that it must be executed in order to infect the computer.
The way a virus works is it piggy backs onto another piece of
software, say your executable ebook, and when that piece of software
is run the virus loads itself into the memory. From that point it
will replicate itself by infecting other programs and then potentially
cause damage to your system.
The second option you gave would not work. By opening the file, even
without saving it, the virus will still have the opportunity to spread
itself into memory and then infect your other programs. The results
would be the exact same as if you had saved it to your hard drive.
Having a "safe" place on the hard drive is not necessary or really possible.
To ensure that your computer is as safe as possible from viruses,
first make sure you have the most current definitions for your virus
scanner. Symantec (the makers of Norton) releases updated Virus
definitions regularly. These are essential in protecting your
computer because they tell Norton what to look for when scanning a
Once you have your updated virus definitions just be sure to scan all
incoming files and programs. You are not 100% safe from viruses even
by following these steps but total protection is only possible if you
don't load any new programs onto your machine.
I mentioned worms above. These are viruses that can infect your
computer without running anything, however they don't come in attached
to files. A worm travels through network exploits, meaning they find
a flaw in the protection of the operating system and use it to their
advantage. These are viruses you typically hear about in the news
because they are able to spread across hundreds of thousands of
machines in a matter of hours.
The best way to protect yourself against Worms is to make sure that
you have the most updated service pack for your operating system and
to protect yourself with some kind of firewall.
I hope this answered your question. If you need anything cleared up
or have any questions, please request a clarification before rating my
answer and I will be happy to help.