Recently I went away for a month and I spent a lot of time worring that the landlord would enter my apartment well I was gone (it happened with a preveous land lord) I was just wondering if she could do that because I was not there for her to give any notice to if she wanted to enter the apartment maby I just worry too much but it has really been bothering me if any one know if she can do this please let me know.

No. Landlords are not allowed to enter your apartment unless
1. They are invited (like when you give them a maint. Request,
2. They give you a written notice that they will be entering (like for an inspection), or
3. There is an emergency.

If the landlord is using a good lease, this should be one of the things confirmed in it.

But I have not been there for her to give notice can see still enter

Legally, all the landlord has to do is "deliver" the notice; and I'd guess that posting it on the door is "legal delivery" in most states (as it is in mine).

I did not understand from your first post that you suspected that she DID enter. If this is the case, then don't jump to assume a wrongdoing yet: Just ask. Tell her you "see someone was in your apartment" and ask her why.