Probably not as rgd1101 said. If you have the charger and are just missing the cord that goes from it to the outlet, and it happens to be the same as the cord from your tower, then yes you can. (I just mean you could borrow the cord) But those cords are dirt cheap and you could just get another one.You can't power the laptop from the tower in any way however.
If you don't have a charger or the cord has a different plug from the tower (which they usually do) then no. You'll need to buy one the laptop is useless without it.