These sort of situations are really difficult to deal with. When you receive "gift" stock the calculation of the gain or loss or push (no gain or loss) when you sell the stock depends on two things: the donor's basis and the fair market value at the date of the gift. Of course most donors don't understand that, why should they?, and then when the recipient of the stock goes to sell it, usually many years down the road from the gift, that information frequently is impossible to determine.
Before doing anything I'd suggest simply telling TurboTax that you "bought" the stock for $0 way back when and look to see how your taxes change, or if they change at all. Long term capital gains are taxed at lower rates than "regular" income, starting at 0%, then 15% and then higher, but if you find out that your "gain" doesn't change your taxes at all, or maybe just a little bit, you might just leave the sale "as is" and go on to other things.
