When I move the physical volume control on my Toshiba laptop it is triggering the 'c' and 'b' key. How come?

Question

For some reason when ever I use the physical volume control on my Toshiba Satellite P305-S8904 laptop, it triggers the 'c' and 'b' key. So I can be writing an email and turn the volume control wheel and I will see 'c's just appear. It is particularly annoying when watching movies in VLC player because the 'c' key is responsible for image cropping.

Actually to be more precise, whenever I slide/turn the volume control to the right I will get the 'c' key but when I turn it to the left I will get mostly 'c's but sometimes 'b's.

I know it sounds like I am talking about the grades I generally get at school or that it sounds highly improbable that this is happening but, i assure you that it is in fact happening and very annoying. So the questions are:

1. Why is this happening?
2. How do I stop it?

Answer 1

It is not that surprising, most keyboards' hardware does not contain a separate contact for each key, but is rather based on a matrix with each key triggering two contacts. In addition, the path from the keyboard to the CPUs often contains translation hardware busses (e.g. USB) etc., again, you get a mapping between keys to contacts that is not 1:1

In other words - this is almost certainly a hardware problem.

As to fixing it, if it not under warranty that would be voided, I would have tried to open the thing up and try to clean the relevant areas.