As stated above get a new one. They are cheap insurance.
You can reuse the old one as hrsdennis says but I think your just putting off the inevitable.
I got my pool free from a friend. It was 4 years old. I knew nothing more than how to put them up by helping friends.
The day I took it down I folded up the liner,Still wet, stored it in my shed for 3 years till I finially put the pool back up. unfolded the liner, which by now stunk to hi heaven, rinsed it off, put it in (the skimmer and return holes are a real pain) and now 4 years later am looking to replace the liner. Wish I found this site first. Good thing is while the pool is empty I can fix a few things I don't like about my original install.
Hope this helps.