My mouse and keyboard work fine in Ubuntu, as well as grub. However, when I boot into Windows 7, I cannot get past the login screen because the mouse and keyboard do not work. The lack of light on my mouse indicates that it's not even on. This happened before when I tried to manually install Ubuntu (partitioning myself with gparted) so I reinstalled and let Ubuntu do everything for me ("Install alongside Windows 7" option) and I thought that fixed the problem because the mouse and keyboard worked twice in a row. Now, however, they have stopped working again. I am using a Logitech K120 keyboard and a Deathadder mouse. Both are plugged into usb 2.0 ports.
when you boot from win 7 try to plug out both mouse and keyboard & plug them again at same port. If it doesn’t solve your problem then try different port.