When you like run windows, you don't need restart the machine because exist VirtualBox, this program is the best virtual machine that i know. You only need install from automatix or some repositories of Ubuntu is depence of your version of ubuntu, but i only probe in 7.04. I haven't got explain the instalation i only explain the configuration with folders and devices usb.
1. The first open your virtual machine and after you go to the menu and in the configuration menu and after directory share you need add new shared folder ex.(/home/user).
2. The second you need have the virtual network adapter active, and then you start the virtual machine.
3. The third open a cmd in windows, in menu start -> execute
4. And you need put this line.
net use x: \\vboxsvr\carpetacompartida
If the out is succesful you only go to the My_PC and you open the net folder X.
Now for the devices usb.
Edit the file /etc/udev/rules.d/40-permissions.rules (for this, you must have administrative privileges) Search for the following lines
# USB devices (usbfs replacement)
SUBSYSTEM=="usb_device", MODE="0664"
Change them to the following
# USB devices (usbfs replacement)
SUBSYSTEM=="usb_device", GROUP="usbusers", MODE="0664"
Finaly, Restart your PC.