nope, i never laugh at someone who asks a question because they don't understand something, no matter how simple it may seem to others, we've all been there, lots and lots i don't fully understand about pc's including hard drives.
easiest way maybe is if you think of it like a library, to find a book you'd first look at the cards that tell you were it is, before going to find it, now when you delete a file/data on your pc, all your doing is removing the card which tells the pc where the book is, but in reality the book/file/data is still there in the library/on your hard drive, so you'd find it eventually if you look through everything, and that's all programs like recurva do, look through everything.
now when you delete a file/data from a pc(remove the card that tells it where the data is stored) then use a program like ccleaner to go and write zero's to any empty spaces on the drive, what it's doing is checking the library cards telling it where a book is, then going to all the spaces where no cards say there's a book, and if it finds a book(your deleted data) removes it leaving a gap/zero there, so now when a program like recuva looks through everything it won't find any books that you can't already see are there from the cards.
ok there is a bit of a debate about exactly how good just writing zeros to a space is at permanently removing data from a hard drive, and some programs write random numbers there first then write a zero last to make sure it can't be recovered but to be honest unless you take the drive apart and use special forensics on the platter, i think just writing zero's is good enough to foil programs like recurva from ever being able to recover your data.
seems ccleaner does actually zero a complete hard drive too, not just the empty space if you so choose, of course zeroing a complete hard drive necessitates an os install, where as just zeroing the empty space would leave your os intact and just clear any deleted data. :-
http://www.piriform.com/docs/ccleaner/usin…free-disk-space
hope this gives you a little better understanding of how a pc's os stores and finds data on the hard drive anyway.
best way to learn about such programs is to use and experiment with them, including recurva, and like you said acronis is your friend when things go pear shaped.
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another "caveat" for you, don't experiment on your daily machine unless you have to, always use a 2nd pc if you have one.
just read that ccleaner link more thoroughly and looks like it won't zero a complete hard drive if it's the one with os on(boot drive)
For safety reasons, this feature is disabled for the boot drive.
