Black screen in Windows XP
Description of problem:
When starting the installation of Windows XP (or Windows 2003) the screen in VNC stays black while the installer is in text-mode. During the second half of the installation, where it switches to graphical GUI, the display becomes visible again.

This problem never happened on 9.0.1 and below, so is a regression in 9.1.0
Steps to reproduce:
1. Start the Windows XP installer
2. Connect to VNC
3. Screen stays black