forgot - i have windows 7 home premium in spanish...
i've installed another software and no problem.
You may want to try the following:
Run this fix from Microsoft: http://support.microsoft.com/mats/Program_Install_and_Uninstall. Uninstall all traces of any versions of Reader. If you want to reinstall Reader, download its full installer from http://get.adobe.com/reader/enterprise/
Maybe it could have worked, but I was so desperate to do my homework that I did a OneKey Recovery and reinstalled all of my softwares. And everything turned out fine, including Adobe Reader.
I didn't know how long it would take someone to answer this, but I'm impressed that it actually was pretty fast.