XP Mode powers down in win7.

Hi,

I install Virtual PC- XP Mode on windows 7 pro. 64bit. Previously I was using Win XP on my old computer and a USB camera (with WIN XP only driver) that was working fine. When I install the camera driver and try to use it with included software and with Amcap, XP Mode suddenly powers down. XP mode can be started normally like nothing happened.