i have the HP Pavillion dv9000, it came with these hard disk drives. OS(C

DATA (D

and HP_RECOVERY (E

. those are all the drives. it has 320ish gigs in total i believe. i'm just wondering why when i click computer and go to Program Files there are 2 separate folders:
Program Files
and
Program Files (x86)
both folders have different things in them, though the (x86) one has many more programs. except they both share a bunch in common, such as
Windows Calendar
Windows Collaboration
Windows Defender
Windows Live
Windows Mail
Windows Media Player
Windows NT
Windows Photo Gallery
Windows Sidebar
is there any reason for these to be in BOTH program files folder? and what's up with this who (x86) thing. what does it all mean?
it seems vista already takes up an increadible amount of room, so do these doubles increase the space vista uses?