Yesterday I connected a webcam to Windows 7, I had to download drivers (about 100MB of it from Logitech) only after this it started working.
Also the same day I wanted to install my old HP 4300C scanner, connecting it to Windows 7 and using some old driver for windows xp didn't make it work. There are no drivers for Windows 7. The ones for XP are also quite old and are some kind of a "remastered" Windows 95 version sometimes they don't work.
When I did the same on linux (Debian Wheezy, default kernel 3.2.x) both devices just work I didn't have to do anything apart from running an application that uses them (Skype or scanimage).