64-bit vs 32-bit and hardware concerns...

I have a client who is currently using Windows Professional 32-bit. I want to move her to Windows 7 Professional 32-bit; I think that is the correct migration path for her.
I go to the DELL site to create a few virtual machines for her. I notice DELL is only selling 64 bit computers with Windows 7 64-bit.
I called DELL and asked the agent what’s going on? The agent told me that it was not necessary to use a 32-bit OS and hardware because 64-bit is backward compatible. My eyes were wide open! So I checked around and I did find a page that talked Windows 7: 64-bit versus 32-bit Windows 7: 64 bit vs 32 bit?
My client has some old okay some dinosaur equipment that she would like to run under Windows 7. It appears to me that I would need Windows 7 32-bit if she is ever to have chance for her legacy hardware to function under Windows 7.
Then I heard that If you are using Windows 7 HOME you can’t take advantage of going to Windows 7 Professional and use the virtual area that allows legacy software to run under Windows 7 (Windows 7 compatibility mode).
Can someone help me get my head around all of this?
Thanks!!!!

Windows 7 64-Bit will run most of the 32-Bit software titles. However hardware will require 64-Bit drivers to work in Windows 64-Bit install. If your client has old equipment that only has 32-Bit driver support. It might be wise to install the 32-Bit version for compatibility with the older equipment. However if your client chooses to upgrade in the future to 64-Bit, A clean install using the very same key used to activate will be all that is needed.

Please also keep in mind this will also limit the amount of memory that the machine will be able to see. 32-Bit can only address 4GB memory, some of which will be used by other resources leaving an average of 3GB usable.


Windows 7 Application Compatibility Mode & Windows XP Mode are two different things.

1. Application Compatibility Mode - Allows you to run any application under Windows 7 with a previous OS Mode for Compatibility.
2. Windows XP Mode - Allows you to create a Virtual Machine with XP SP3 installed, which is only available in Windows 7 Professional and greater.

Thank you clifford_cooley for replying !

Now I can clearly tell my client what their options are!!!!!
Better yet I can move my office computers smoothly to Windows 7!

Cheers!

also adding to this, 64 bit allows for use of ram above 4 GB where as 32 bit can only 3.5 - 4GB of ram and there is also a speed improvment in using 64 bit over 32 bit windows 7 OS's. It all depends does the consumer want to pay to up grade or to stay we're ther are.

Thats what I did clifford, I have mapping software I was told wouldn't run on 64 bit, so I installed 32 bit, but the 64 bit option is available on the same installation CD so I can easily switch to 64 at any time in the future.