Gray scale prints a greenish color

I am a teacher, we are currently using CorelDraw X6 Home & Student to create handouts and awards for our students.  We like them bright and colorful, in the past we used CorelDraw X3 and never had an issue, but now we have two problems.  The first when we use a gray scale it prints a greenish color and the bright colors print dull and faded.  We print only on bond paper and card stock (no gloss).  Could someone please tell me what settings I should be using, keeping in mind that I am a novice here so I'd appreciate it if you could keep it simple for me.  Thanks.