Although we can try to help.
I don't know VB worth crap, so there could be an easier way, but I'd say that you could check if it begins with a '-,' strip it off if it does, convert the main part to a number, then multiply by -1.
IE, if you have "-5" in a file, you take off hte negative ("5"), convert it to a number (5), then multiply by -1 (-5).