Knotting up & Tangling Line?

I just found an old rod and reel that I thought I had lost years ago. I LOVED both the rod and the reel. They were a GREAT setup. One of the many reasons that I loved the setup was that it casted so smoothly and had such great distance. With little more than a flick of the wrist, zzzzzzzzzzzzzzzz the line was humming out. You could hear it and see it but you couldn't even feel it. SO, I was really excited when I found it! I took it out to my street (which was dead because of ice and snow) and tried a few casts. It sucked! Every cast got knotted up and tangled. I cut the line, tied my weight to it and casted. It got knotted and tangled, again and a again. I kept cutting the line and starting over. No help. What's the deal? Is the line "old" do I need to re-spool new line? Overhaul the reel? Any ideas?