Go into task manager select the processes tab and end explorer.exe then alt-tab back into age of empires
Note: this will make your task bar disapear and any open folders
To restart explorer open the task manager agian in the aplications tab hit new task and type explorer in the box
The colours change because of the Aero theme's poor handling of colours
Edit:
You can also make a batch file with the following lines and place it in the same location as your age of empires 2 executable
taskkill /F /IM Explorer.exe
age2_x1.exe
Start explorer.exe