How can i Install Norton Antivirus to my 64 bit Vista.. ?

i bought new HP laptop a week ago.. in that only trial version was there.. so now i tried to change the Norton Antivirus 2009.. when i tried to install... error message showing hat, this version does not support for 64 bit version.. how can i change back my settings for 32 bit?
is it like going back to low version is good?

If yes.. how can i do that.. give me the tips.. pls..
Thanks

norton 2009 works on either 32bit or 64bit
not sure why you getting error message
try downloading it and Norton AntiVirus 2009 - Free software downloads and software reviews - CNET Download.com

put ure key in to activate it, what i presume you have