Hello All,
I am a student working on an XNA project for a CS1 type class and need help with my project for a final exam.  I am creation a "Pac-Man" type game with all origional artwork.  I have everything working correctly for the most part, however, the part that I am having issues with is how to make the sprite not travel through walls.  The gist of the program is it needs to be simple, as I stated before, this is a CS1 class.  I have initalized all the pellets with an array of Vector2's and a for loop, and the "map" was created by aother student in the group using Paint.Net.  If someone could provide some help I will be very thankful.
    

If the map was drawn in Paint.NET, you will need some way of programatically knowing where the walls are. I'd recommend setting up a Wall class, which creates each section of wall as a rectangle. (The wall you define yourself can be invisible, if you have a background ready-made). Then, for the actual collision detection, you can use a class called BoundingBox. It's actually made for 3D, but you can use it for 2D just fine by only defining the first two values. It has a nice Intersects() method which determines if one BoundingBox is partially inside another.

The Rectangle class also has an Intersects method for checking collisions. No need to use a 3d bounding box when there's a perfectly good 2d class. You use the Intersects method like this: Rect1.Intersects(Rect2) and it returns a boolean value;

To handle moving pacman and the baddies out of walls after detecting a collision, I would use a for loop that moves pacman 1 pixel in the desired direction, checking for a collision each time. It's not efficient, but since you only do this when a collision is detected and you have at most 5 objects checking for collisions at once, efficiency won't matter.