I have just discovered another problem with XP Mode. I had not used it for a couple of months. During that time I had installed SP1 on Windows 7 Professional x64 and did not notice any trouble in day-to-day use of Windows 7. I just realized as of this evening the SP1 for Windows 7 seems to have made XP Mode go haywire. I'm including these links from Microsoft Technet that discuss this problem for reference:http://goo.gl/0KbPHhttp://goo.gl/SpiWq
I have not personally tried the fixes yet due to lack of time at present. I'm really annoyed that this happened. I will post back with my results when I try the Technet suggestions. (XP Mode does work without the Integration Features but it is much more cumbersome, especially when dealing with releasing the mouse.)
Meanwhile I hope that this information may help someone else who may be puzzling over the same issue.