Right after installing Windows XP inside VirtualBox, I've found out everything works fine except the screen. Even though pressing (Right CTRL + F) was changing the Windows XP running window to FullScreen the XP screen was taking only a part of the whole screen area, where almost half of the screen was visible as simply staying blank.
A bit of research and I found the issue is caused by missing VirtualBoxGuestAdditions .
VBoxAdditions is a package which should be installed inside the VirtualBox by navigating to Devices -> Install Guest Additions
Virtualbox offers a download of a VboxGuestAdditions_4.1.2_Ubuntu.iso from url;
http://dlc.sun.edgesuite.net/virtualbox/4.1.2_Ubuntu/VBoxGuestAdditions_4.1.2_Ubuntu.iso, anyways this download fails since the URL is currently unavailable.
To fix this two ways are possible:
1. Download VBoxGuestAdditions.iso from here and put it in directory /usr/share/virtualbox , e.g.:
root@ubuntu:~# cd /usr/share/virtualbox
root@ubuntu:/usr/share/virtualbox# wget http://www.pc-freak.net/files/VBoxGuestAdditions.iso
root@ubuntu:~# wget http://www.pc-freak.net/files/virtualbox-guest-additions-iso_4.1.2-1_all.deb
root@ubuntu:~# dpkg -i virtualbox-guest-additions-iso_4.1.2-1_all.deb
Next to enable and install guest additions once again use menus:
Devices -> Install Guest Additions
The screen to appear next will be similar to:
Further on follow the few dialogs to complete the installations and integration of Guest Additions and restart the Virtual machine and hooray the Windows will appear in Full screen in VirtualBox !