Windows 7 32 bit

[#1]

If you were using windows 7 32 bit and then installed a  64 bit program on the computer with a dual processor would it work ? or would there be problems doing this ?

[#2]

If the program is specifically designed for the 64-bit version of Windows, it won't work on the 32-bit version of Windows. 

[#3]

64bit programs will not run on 32bit OS's - 64bit is newer and 32bit never catered for what didn't exist at the time.
64bit OS's however WILL run 32bit programs due to what they call 'backwards compatibility'. Despite all the paranoia about it years ago, it does this rather well and even seems fine with hardware device drivers that are 32 bit.
I'm afraid if you need to run a 64bit program you'll need a 64bit OS.

[#4]

Quote from: Sprite

I'm afraid if you need to run a 64bit program you'll need a 64bit OS.

Well not exactly, you need 64-bit hardware. 
Whether the program will then install and run in the presence of a 32-bit OS (on 64-bit hardware) will be down to how the program uses the OS.
Thinking way, way back to good old DOS for example, there were memory extensions of various types that DOS couldn't address but some programs could.

[#5]

Quote from: HPsauce

Quote from: Sprite I'm afraid if you need to run a 64bit program you'll need a 64bit OS. Well not exactly, you need 64-bit hardware.

Lol.. there's always one 

[#6]

Quote from: Sprite

Lol.. there's always one

2 at least including you.  
However, it's NOT a silly point because many 64-bit apps will likely only be using standard/32-bit OS services/interfaces.
Memory management is likely to be the "trickiest" area.