WinXP mode and Virtual PC

[vsub]

One maybe stupid question but I recently started using anything other than WinXP.
Are both things different WinXP mode and MS Virtual PC with WnnXP or WinXP mode opens a window like MS Virtual PC or the program in WinXP mode is opened like any other program(you can't or you can barely see the difference)

 

[VistaUltimate]

Having Windows XP installed in Virtual PC has some differences from Windows XP Mode.

Windows XP Mode lets you work with some applications installed in Windows 7 that have compatibility issues with Windows 7 while Windows XP in Virtual PC does not.
You also need your product key to activate Windows XP in Virtual PC,whereas Windows XP Mode is pre-activated,so you don't need any product key.
Actually,Windows XP Mode is Windows XP Professional SP3 32-bit.It is pre-installed in a VHD,so you don't need to install it after downloading.The download is almost 452 MB in size.You need 1 GB at least to install Windows XP Mode.

These are the differences between each other.