Kinda thought virus as soon as you said something was taking control of your mouse
![smile.gif](style_emoticons/default/smile.gif)
Also XP fully supports USB keyboards, It just has to detect them like any other USB HID and that takes time. You DO NOT need to have a PS2 keyboard to install XP.
Hell I'm pretty damn certain every OS from 98SE to 7 has supported USB keyboards off the bat.