listbox problem

Hi,
First I want to appologize for my bad English,I hope someone will understand me.
I'm creating a new appliction for my company but I'm stuck.
Here is my problem.
So I created a form with a listbox(1) within data based on a table. Then I created another listbox(2) because I have to select several things from listbox(1). So I placed a button on my form and I can add my selected data into listbox(2).
But I also placed a button on it to remove data from listbox(2) in case of I added something wrong. This also works but when I now want to add new data,he also add the data I already removed. And then second thing I want to use the data of listbox(2) as criteria for a query. It works when I use a combobox but not with a listbox.
Can some help me please??

Thx

I forgot to say that I work in Access97.