1. Shut down the virtual machine in Windows Virtual PC, so to exit the Windows XP Mode.

2. Open a command prompt window with elevated privilege.

3. Run the following command 

cd /d "%localappdata%\Microsoft\Windows Virtual PC\Virtual Machines"

REM make a copy of the configuration files

copy "Windows XP Mode.vmc" "Windows XP Mode.vmc.backup"
notepad "Windows XP Mode.vmc"

4. Modify the number in the following sections. For example, you have a computer that has a resolution rate of 1280x800, you can adjust the following numbers to 1024x640 in the ratio of 16:10. This makes Windows XP Mode display more properly in Windows mode. 

 "<resolution_height type="integer">768</resolution_height>"

 "<resolution_width type="integer">1024</resolution_width>". 

5. Save the configuration file.

6. Restart Windows XP Mode

_Contributed by Sharp Xu