Okay, compatibility mode:
Click the game exe -file with your right mouse button, then choose Properties and the click the Compatibility -tab. Check the first option (labeled something like "Run in compatibility mode) then choose for example Win95 or Win98 from the enable list. You should also check the option "Run as administrator" as well. Then click apply and then ok. Try running the game now.
For XP mode, I haven't used it myself as never saw any need for that, so can't help you with how to use it. But the compatibility mode described above should solve the problem.
While I remember, if the method above doesn't work, have you installed the game under Program Files -folder? Something like C:\Program Files\<sub-folders\? I have experienced at times a problems with different softwares which were caused by installing the software under Program Files. You could try to install the game in another folder (remember to remove the old installation first), like c:\ToEE\ or c:\games\ToEE\.
"As we all know, holy men were born during Christmas...
Like mr. Holopainen over there!"
[color="Red"]- Marco Hietala, the bass player of Nightwish[/color]