Populate listbox

Hi all,

I got this excell document with search textboxes.

The quick search works like it should. I typ a search term in and it looks in the columns ID, productname and quantity per unit.
Can someone tell me how i add another column? I can't find the line in the code that determines in how many columns it has to look.

My second problem is that my advanced search doesn't work as it should. It searches but as soon as i delete the search term and the textbox txtID is blank my listbox is empty.
I would like that when the search term is removed that the listbox is filled with all valuables like it is when it's opened.

Can someone help me with this?