If you get an error Error code 0x800703e6 on Product Activation, then your XP is pre sp1 or sp2, follow these instructions....
download sp2
http://www.microsoft.com/downloads/details.aspx?FamilyID=049c9dbe-3b8e-4f30-8245-9e368d3cdb5a&displaylang=en
make an iso of the sp2 exe file.
mkisofs -o sp2.iso WindowsXP-KB835935-SP2-ENU.exe
boot into XP but press F8 immediately to go into safe mode, pointing -cdrom to the iso file of SP2 will mean that the XP machine will have a "cdrom" available when you boot into it.
qemu -boot c -hda winxp.img -cdrom sp2.iso -m 256
Use explorer to get to the cdrom and click the exe file to install SP2. One error will com up about "Invalid Access to Memory Location", no biggy, just hit OK and it will finish.
All done, no more 0x800703e6 |