download cpu-z http://www.cpuid.com/cpuz.php
it will be a zip file. unzip it and then run the exe and then it will collect info about your processor and then under the CPU tab, in the instructions column, see if you have any of these AMD64, x86-x64 or EM64T. if you have any of these then your processor is 64 bit.
this was the direct way. other way, right click "my computer" and then click properties and note down your processor number and then google it and then see in its specs if it is 64 bit or 32 bit. however, if your computer is any p-4 at 3 GHz or above or any new processor than that or any AMD 64 or AMD dual core then you have a 64 bit processor.
you can even see the specs of your computer at your manufacturers site to see if you have a 64bit processor.
but i think that a software's installation will be more affected by the technology of the OS if its 64bit or 32bit than from your processors technology