It will check your system, components,etc and tell you if Win-7 will work on your computer, which components will not work, and which may need updated drivers.
You would have to choose Win-7 32 bit because the 64 bit version requires signed device drivers, which almost certainly won't be updated.
I checked a couple 478 computers last year, neither was recommended. Some folks have updated 478 Motherboards but you have to be computer savy to find, download, adapt, and install the various drivers.
Take a look and download the advisor. Price is right, and you can uninstall it if you don't want it when done.