Most 32 bit programs work fine on a 64 bit OS. However, certain things like 32 bit drivers and low level apps don't work. You'll need 64 bit drivers for your hardware, but 32 bit games and other user level applications work just fine.
64 Bit technology is not being used by just Servers. There are plenty of people on this site alone that use 64 Bit. Not to mention many other places. 64 Bit is now on desktops just as much if not more than servers since any Core 2 Duo can handle 64 Bit. Not to mention any Intel CPU since. Same goes for AMD CPU's as well.
Except for drivers, some things don't have 64 bit drivers and it's impossible to use 32 bit ones, huge inconvenience. Software wise it's no different though.
Not all the CPU's released from that long ago are 64 Bit. I have a P4 Prescott that isnt 64 Bit.
I only said Core 2 Duo cause that is what people are buying now. Not what they used for several years now. I am talking about the present. CAuse this is when 64 Bit is taking off. Back when XP X64 was released it didnt take off and had very bad support. Still does. Vista 64 Bit on the other hand is just the oppostie. It has great support.
Before anyone wants to argue about me with my CPU. Since i do know what i am talking about.
There is my CPUz. No 64 Bit. It is a Prescott. So dont tell me i am wrong. Cause i show my proof.