For most Windows systems, since Windows 2000 the migration from physical to virtual is a snap.
Simply import the mergeide registry hack and power off, use
dd and other tools to dump the full-disk and you're done.
Download the file and then install it, then power off the Windows machine. Make sure the system doesn't have any pending updates or software installs or other reboot-pending changes.
For this P2V operation we make a direct copy of the physical hard-disk. Booting from a LiveUSB or DVD is helpful here, in situations with hardware raids or similar.
Dump from ServerA LiveDVD to ServerB running Ubunut 12.04.
~ # dd if=/dev/sda | nc -q1 -v ServerB 6500
And on ServerB we are listening and writing.
~ # nc -l -p 6500 > /opt/kvm/Windows_2003_Server.sda
Note we are using the rtl8139 adapter. It's just worked better for us vs the e1000.
~ # kvm \ -cpu coreduo \ -m 2048 \ -name p2v \ -boot d \ -drive file=/opt/kvm/Windows_2003_Server.sda,if=ide,index=0 \ -net nic,vlan=$vid,macaddr=$mac,model=rtl8139 \ -net tap,vlan=$vid,ifname=$tap,script=no,downscript=no \ -vga std \ -vnc $vnc \ -monitor $mon \ -usb \ -usbdevice tablet \ -daemonize