computer help: 'FlashGet' is giving me sass.

I used FlashGet overnight last night to help download a demo of Splinter Cell 2.
In the morning for some reason it was “near” completion but still had a few megs to go. (about 7)
I am on Dial-up, so a 118 MGB download does take a while.
Anyway, I checked the window, and although the download wasn’t done, it was at least still working away, slowly but surely.
Then, I noticed we had answering machine messages, so I disconnected.
Now the download won’t restart from where it left off. IN fact, it had deleted itself somehow and I used Norton to get it back. When I place it back into FlashGet, the URL location dissapears. So I went back to the site and copy/pasted the downlod link’s URL. But now, the file size has merely doubled from what it was, and a download error occurs because “file size has changed”.

Do I have to start over? Can I fix this?