Keyboard not switching between modes 2 in 1

I have had my laptop for a few weeks now and I cannot figure out what keeps going wrong with the keyboard.

When in tablet mode, the on screen keyboard only pops up temporarily and inconsistently when I need to fill in a field (eg the internet password).

To try and solve this I try reverting back to notebook mode, only to find that my keyboard is not correctly functioning, as thought Fn key is being held down or something and when I try and type stuff it all **bleep** breaks loose.

Last time this happened I managed to apply a filter to the colours leaving me with a completely  black and white interface, shut 4 windows and restarted my computer. This takes quite some time to undo when you don't really know what you did in the first place.

Also it's REALLY FRUSTRATING!