My second and final conclusion is we need to know how much available hard disk space there is because at minimum this operating system will need 16 GB to be able to run and install properly. We also need to make sure that it will be able to handle the 32-bit version which is the version that will be most suitable for the current specs that have been provided. With all that said it will be a great pleasure in upgrading to the new Windows 7 professional edition upon further review.
Since the computers are older operating systems and are running Windows XP they are going to need to do a fresh instillation. If you do the fresh installation the previous profiles and settings can be carried over through migration. That way the user does not lose all of their previous settings and they can begin to adapt to their new Windows 7 OS.