clueless & need help badly..

[SeaCrit]

Okay so I apologize if this is posted in the wrong place but I really need help with my '03 H2, and I'm not even positive as to what's wrong with it. I'm completely clueless with my H2 and really don't know what to do with it..

My H2 hasn't been driving well ever since my friend hit the rear differential lock (at least that's what he said it was..) but it doesn't indicate that it's on, the light blinked after he hit it but stopped after 15 seconds or so. Ever since then when I make even remotely tight turns or try to reverse and turn it makes weird whining noises and the tires slip on the pavement. I have no idea if this is connected to the button that he hit or not, I just can't figure out what's wrong with it. I just recently started driving this car so this could have a really easy fix I don't know about, that's why i decided to ask.

I would really appreciate some help, thanks!