OS 10.3 - Unwanted scrolling down and shortcuts problems

Hi guys

I really need help on two issues.

First problem is that for some reason the mac starts scrolling down until it reaches the end of the page. That happens when for example, I'm dealing with a webpage or with an image in photoshop that is larger than my display. Even if I try to go at the top of the page it won't stay. It then happens even in the finder windows with the highlighting bar going from the top to the bottom item of a list. I then have to relaunch Finder or restart to get it to work again.

Second problem, that I don't know if it's in any way related to the previous one, is that the shortcuts Command-N and Command-Shift-N don't work in Finder or any application. They used to work normally and I noticed the problem around the same period that the scrolling down thing happened for the first time. The rest of the shortcuts that I'm generally using work fine.

I'm using 10.3.9 on a mini

Thanks in advance for any help or suggestions