Go to any Home Center and buy yourself some gutter seal and a caulk gun. It's in the paint department, but it's NOT pait. No guarantees that this will work. Before I had my gutters replaced w/seamless gutters, I sealed one seam 2x's and it still leaked! When I got new seamless gutters, instead of having the right angle put in the gutter like the old one (which would defeat the purpose of a seamless gutter), I had a straight gutter installed and ran the downspout over to the side of the house first, then right on down. No seams, no leaks!