Scottish slang. Refers to persons behaviour. Daft, nutter, nuts, silly, "not right in head".
When someone joins a snapped CD with sticky tape and loads it into the CD drive. After a moment of some unhealthy noises, the person looks at you and asks "Do you think it's broken?". This person is commonly referred to as a BAM!
These people exist and yes, he also managed to screw a perfectly good CD drive...