... yes, of course, 'quick' is relative. You have VirtualBox installed in Windows 7 - and Windows 7 is a very lame OS, which does not leave enough CPU power for applications like VirtualBox.

The last version of VirtualBox is 4.0.10. For USB-support you need the extension pack. To read the manual use [F1].

For each virtual machine you want to run in VirtualBox you can do many decisions. For example 'System > Processor > 2 CPUs and many other things.