Hm... First of all, I'd try to figure out what makes the recovery process go wrong. If done from a usb stick, try reinstalling it directly from the dvd, if necessary using a borrowed drive. Because when more serious trouble rears its head you *have* to be able to have a working recovery procedure at hand. That's more important than modifying the task bar.
(It's possbile that it disappeared by clicking the little arrow icon in the lefthand corner maybe. I'd also search the forums about which files to modify with regard to the task bar itself.)