My MacBook Pro keeps on randomly scrolling on webpages, putting several spaces when I don't press the spacebar and only sometimes makes a space when I press the spacebar. Why is it doing this? Do I have a virus?

10-11  Source: Network gathering  Views:3 

I am currently struggling to write this due to my very erratic spacebar. When I press it, it only creates a space about two thirds of the time. When I don't press it, it creates spaces, often several, in the middle of words.  This is incredibly annoying and time consuming when writing. If I'm on iTunes or DVD player, it means the media is constantly stopping and starting.
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!
You are still under warranty.  Call Apple Care. Make sure you get a case number as all repairs have an additional 90 days of warranty. 
#1 - You have 14 days from the date of purchase to return your computer with no questions asked.
#2 - You have 90 days of FREE phone tech support.
#3 - You have the standard one year Apple warranty.
#4 - If you've purchased an AppleCare Protection Plan, your warranty last for 3 years.   You can obtain AppleCare anytime up to the first year of the purchase of your computer.
Take FULL advantage of your warranty.  Posting on a message board should be done as a last resort and if you are out of warranty or Apple Care has expired.
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