Folks have been successful with the 32-bit version of Win 7. Unless you have a lot of computation or such, I am not really sure why you want to use a 64-bit system. A lot of compatibility issues have been reported for many software products with 64-bit OS. I have seen a few reports where I interpreted the information that they had AA8 working under Win7. Office 2010 is only compatible with the updated AA X for the PDF Maker functionality.
As far as the installation of AA8, you would need to deactivate it from your old machine and then install it (need the download file that it sounds like you tossed) on the new machine. If you have registered (or register the current copy you are using) with Adobe, you may be able to contact them to get a new download of AA8. Of course, you will also need to installation key. It is sounding like you may be missing some of that. If so, you may have no choice but to upgrade to AAX. You can check the upgrade costs at the Adobe store. The concern still might be that you need the key code and such for your current copy to be able to install the AAX version. There are some other folks that have dealt with the upgrade that hopefully will come by and give their input.
Thanks for the information. In answer to your questions:
1. I do have the full key.
2. I want to use the 64 bit Windows 7 because I am using the machine for some heavy video editing and the 64 it machine is better for it.
3. The version of Window 7 I am going to use will allow me to use programs designed for 32 bit, so that shouldn't be a problem.
I was hoping that I wouldn't need to do a new download but could copy the files I have on my old machine over - but don't know which one is the installation file.