Dell Inspiron 15 N5010 :: Mouse Pointer Changes Shape And Starts Scrolling Automatically

Sometimes my cursor changes into a shape that's not in the list of possible mouse pointers and I can't print screen it, because it's not in the image when I search it..

It looks like this: 2small white triangles with a white line in between. Sometimes they point left and right, and my pc starts scrolling sideways, and sometimes they point up and down and it starts scrolling downwards.

I updated a lot of drivers and restarted my pc. I scanned for viruses, but nothing could be found.

It happens with or without a mouse inserted. It's really annoying, because surfing on the internet becomes frustrating.

O yeah, that pc doctor from the dell site did not find anything either.

It's a relatively new inspiron laptop (less than a year) and I have this problem since the beginning.