Q: My mouse (non-wireless) just recently started to not scroll down. It scrolls up and from side to side. How. Can I fix this?

Is this an Apple mouse or a third-party model?

And is the mouse itself, or is this a problem with a scroll ball on the mouse?

If it is the roll ball, move the mouse around on a bit of sellotape tape (sticky side ) and it does a pretty good job of cleaning it. Don't keep going over the same bit of sticky area - move it around the tape - otherwise any dirt you get out might get put back in.

How to really clean your Mighty Mouse (with caution!):

http://support.apple.com/kb/HT3226?viewlocale=en_US

and:

http://web.mac.com/karelgil/iWeb/MacWebSite/MightyMEng.html

http://www.linklink.co.uk/apple-computers/cleaning-inside-and-dismantling-the-ap ple-mighty-mouse/

Did you try cleaning it?!

I once had a u.s.b. mouse and I cleaned the little  scrolling button with Methlated spirits.be sure while cleaning the button that you lightly roll it  so as to get all the dirt or whatever out.(sometimes the sweat from the hand gets in,

so it might be an idea to make this a regular maintainance thing ! )