If you are looking for in-place migration of Windows XP desktops, you could use
Laplink’s PC Mover. But if you want to preserve your Windows XP desktop and
switch back to it when you need to run an application that doesn’t work on
Windows 7, then you should consider Zinstall’s XP7. It creates an XP virtual
machine (VM) with all of your old applications and files just a mouse click
away. “Consider” is the operative word, however. The product idea is sound;
the implementation is lacking.
You can read the entire review here.