CAPS lock turns itself on/off randomly

[AliGo]

Recently my keyboard has been behaving strangely and after a couple of weeks of working with it and trying numerous things to fix it - I've narrowed it down to the following:

* randomly the CAPS lock on the keyboard (laptop and external) turns ON

* as a result when I click on an open item (e.g outlook, chrome, itunes etc) a new session starts

* also the mouse will not scroll down/up a webpage, word, excel etc etc. however it will scroll if I have a settings window open

* when I click on a webpage the text above the cursor is automatically selected.  Same goes with outlook, its impossible to click on one email, numerous are always highlighted.

* this repeats fairly often and this afternoon its happening every minute.j

What I've discovered so far regarding how to turn it off:

* i've turned on the screen keyboard to see what keys are selected.  I've noticed that the SHIFT keys are highlighted to indicate its ON.  it then takes some clicking on the shift keys to turn it off, it just doesnt turn off at first press.  Sometimes I get the shift key to off (it isnt highlighted on the onscreen keyboard) however the behaviour described above is still occuring.

After the shift key/s are deactivated I hold down the right shift key for 8 seconds or so and all goes back to working normally for a minute of so.

I've noticed on the onscreen keyboard that the right shift key on the laptop does not indicate the shift key has been pressed when I press it.  This does not occur when pressing on the right shift key on the external keyboard - it works as expected.

i'd really appreciate some help with this as its driving me insane and rendering my laptop unusable (and I love my HP laptop).

If you need further details, please let me know.

Thank you so much.

Alison.