How to close forms opened from other workbooks...?

I have a form that is loaded(show) from Personal.xls.
Other workbooks can then be opened.

Q. how is it possible to check if the form (Main.FRM) is open and close it
or reference a listbox item if it is open.

Is there a way of:
If Userforms("Main") then
ThisTextbox.text=Workbooks("Personal").Main.TextBox1.Text
end if

Thanks for any Help.
Andrew