Any "current" PC is 32 bit capable. You should only worry if you're trying to go with 64bit(which I wouldn't advise...) At least Windowx XP X64 had some pretty major compatilbity issues.
The dual core AMD model there is faster then the AMD64 3500+ single core model used here that will support 64bit versions of Windows as well as the 32bit versions. If you are currently running any version of Windows past the original release of Windows 95 prior to the OSR2 service pack you are already running a 32bit operating system. For Vista you will eventually want to move upto 2gb of memory on ths system however due to the addtional while optional features included in the 5 new versions of it.
oo im sorry , i should rephrase my Q. i mean is my machine capable of running 32bit , i know my system is powerful enough to run Vista , but i mean 32bit
As explained earlier if you are already running any version of Windows you are already running one 32bit main application there. That's what Windows is one large application with a good number of small ones loaded into memory. Gee? Where's that screen shot of an old "8bit" dos game that runs in a virtual dos window on Vista? A 64bit cpu means that you can run a 64bit version as well as a 32bit one. The newer cpus are designed for this. "duke nukem where are you? you old 8bit pc game"
(gee? this one getting old now. I'm going to have to run a dos window with the new background on the Vista secondary drive here. )