You need to fill out and submit an Adobe nine PDF form that is only compatible with Windows Vista and you have installed Windows 7. Can you use, download, or install Windows Vista just long enough to fill out that form without losing any of your Windows 7 files? You need to know if you can opt to use more than one operating system on a same computer or find an alternate solution?
You can try running Adobe Reader nine in Vista compatibility mode. Right click Adobe reader nine desktop icon or your "Start", "Programs", then "Adobe Reader nine" menu item. Select "Properties" then click compatibility mode tab.
In a compatibility mode drop down list, choose any Vista choices available. Click OK and then try running Adobe reader. Hopefully, it will let you enter responses into that PDF form now.