I wanted to know if i can upgrade from Vista Home 32bit(OEM) to Vista Ultimate 32bit/64bit (retail upgrade version) ? is there anyone who has idea about it ad can clear my doubt? actually i have made my mind to upgrade to either 32bit or 64bit as i don't want to loose any data doing clean install.
You can upgrade from Vista Home 32bit(OEM) to Vista Ultimate 32bit but you can upgrade to Vista Ultimate 64bit. For installing 64bit you will have to do a clean install and you will loose data installed in that particular drive. If you don't want to lose any data than go with Ultimate 32bit, Hope that cleared your doubt.
Yes you are allowed to use 32bit installation DVD for installing 32 bit version on a 32bit computer but you are not allowed to use 64 bit installation DVD for installing64 bit version on a 32bit computer.