I'm so sorry if this is in the wrong place!! I couldn't find anywhere else to ask, and I'm not even sure if anyone on here will know the answer to my question... but it's Sunday and all the good computer places are closed, and I'd really like this solved tonight.

Anyway, about a month ago I brought my Mac in to get it fixed. They ended up completely putting on a new system program, so I pretty much got a brand new computer. But it has passwords on it that won't allow me to do admin things like install programs, create other accounts, things like that. I tried every single password that I had on the computer before it died and nothing has worked. I would be shocked if they put a password and didn't tell me! So my big question is: Does anyone out there know if there's a way that I can get in and change the passwords or take them off without knowing the old one? I'm so stuck!! Thanks everyone, and again, sorry if this post is in the wrong place!!