Hi Mr E,
i did a quick search and found these similar problems from the microsoft forums

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, in the applications tab hit new task and type explorer in the box, press Enter
The colours change because of the Aero theme's poor handling of colours


alternate solution:
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

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alternate solution
Right click on the file which is launching AoE > Properties > Compatibility tab > check Disable visual themes