I'm a bit of a newbie when it comes to installing a new OS (I don't really do it too often) but I really want Lion and to keep all of the files I have on snow leopard. If I do a clean install will it wipe my HD? How do I clean install? Are there other options of installing Lion? And finally, will Snow leopard be wiped from my HD (just the OS, not my files) when lion is installed? Thanks!