Help with a couple of Xbox games

[NICKtendo DS]

NTSC games on a PAL console? Region-lock doesn't like that. Don't buy games for a console from a different region, that's the best advise I can give you.
But since the harm is already done, all I can say is you're f'd. Unless you modify the console, which brings its own heap of trouble, there is (for as far as I know) no way to make your PAL European X-Box read the American NTSC game disks.