When I am on webpages they will often scroll straight to the bottom, and when I try to scroll back up it won't allow me to and the screen will look like it's jumping, like my instruction for it to scroll up is fighting against an external instruction forcing it down. This 'fighting' effect is also seen with the spacebar issue when it makes several spaces and I press backspace to try and delete the spaces.
I have a MacBook Pro bought in July 2012 using Mac OS X 10.7.5. I use ESET Cybersecurity, which hasn't identified any viruses. I have deleted all internet downloads that aren't from well-known websites, yet the problem persists. It has been happening on and off for about a week, during which time I have turned the computer on and off many times, though today it has been far worse than before. I am worried I have a virus, though can't seem to locate one.
Please, if you can shed any light on the situation, please do! I'm not a techy person at all, so there may be a very obvious reason and solution for this, in which case I apologise for this waste of time. Still, any help would be very very appreciated, thank you!