Did I just mess up Windows?

I'm using Windows Vista. I right-clicked on an .exe file and accidentally ociated all .exe files with Adobe Acrobat Reader. This means I can't open .exe files and I don't know how to restore it back to normal. I uninstalled Adobe Reader (which worked in restoring it back to normal) but I can't read .pdf files now. How can I have it so I can open files and have Adobe Reader on my computer?