Whenever I use a drop down, it automatically scrolls to the top?

Hi guys, I'm not sure what the problem is, but whenever there is a drop down option and I select an option, my computer automatically scrolls to the top of the drop down as if the up key was held down on my keyboard.

It even happens when the keyboard is unplugged?

I'm running Windows 7 64 Bit, how can I fix this issue? It's sort of been on and off for the past few days.

It also occurs when I open a folder in the start menu, when I click the folder the start menu just scrolls to the top and opens the top folder.

Ah nevermind guys, it appears to be a problem with my mouse!