Aside from manually resizing the window and then closing (with the little X box) and reopening to see if the resize took, you can read through this noted fix for XP window problems:
I have done something to cause every window that
opens up to be tiny!!!!!! I looked this up on this
forum, and tried to follow the instructions, but it
didn't work for me. (Clicking on a desktop icon/run?)
My computer may be possessed.
I have Windows XP, and I'd like each screen and
be maximized when it opens.
Please help me. If there is another place on the forum I should look, please give me a link to it.
Thanks in advance.