|In reply to Comment 176 (Kymberly Fergusson):
"You wouldn't believe the rate of cheating/copying/plagiarising in Computer Science... we caught 80% in one subject alone on one assignment (of 10 assignments in the semester). Typically we catch a quarter of the students in each subject for each piece of assessment, and many of those are serial offenders. It's quite depressing."
You need to set assignments that require original thought from each student, and a different answer from each. Not easy if they are beginners.
Alternatively, get all the work done in a classroom situation, - replace lectures with reading assignments and make the classes 100% practical. Only work actually done in the labs under the eye of a teacher to be accepted.
Of course some will still cheat, but it gets harder.