What drivers should I install to use the trackpad "two finger swipe" on Windows 7 running under VirtualBox?
Solution 1:
Multi-touch gestures aren't built in to Windows. you'll need to use third party utilities to get these sort of functions. Check out this page for instructions on how to get the various mac functions working in Win7.
Solution 2:
Those gestures are specific features of the Mac operating system, so they are not supported on Windows by default.
Elan Smart Pad is software which will allow you to do thinks linke gestures on a trackpad, so maybe there is your solution?