I live in Illinois and last night me and my boyfriend gave our roommate 30 days notice of eviction. Now she is saying that I cannot legally kick her out because she has paid rent and everything else. Problem is, she is NOT on the lease. I have talk to local authorties and the county clerk because she said that she talked to a officer and he said that we had to have our county sign the eviction notice in order for her to be legally kicked out and they said that that is not true, but if she does not start to look for a place or looks like she is indeed going to stay that I can file something and pretty much take her to court. I don't want this because it just makes the situation harder than it should be. We are kicking her out because she has repeatly broken verbal agreements with us over 5 months and we had enough. I want to make sure I cannot get in trouble for this and I do plan on changing the locks at midnight on the 30th day, even if she moves out before then I'm changing them because she seems very unstable and has already stolen things from past roommates.

You cannot legally change the locks until you have received a judgment for eviction from the court and the sheriff or constable has performed the eviction.

If you have given her a written 30 day notice that her tenancy is terminated, then if she hasn't moved out on the 31st day you can file the lawsuit for eviction.

No, you can not change the locks. After the 30th day if she is not moved out, it gives you the right then, to file and take her to court to make the judge order her out.