Vicky, from the age of 19 to 37 I always had running knee problems and during that time tried to run every few years only to give it up again. At 37 I wanted to run a half marathon and spoke to some runners for advise. I finally decided to take a holistic approach that consisted of the following:
1) Saw a physio that gave me stability exercises and stretches to do.
2) Lost some weight by improving diet and cross training / swimming.
3) Took 3 grams of Glucosamine a day, from a health food shop!
4) Started strength training, such as squats, deadlifts, core workouts and much more. I used a book called "How to Run" by Paula Radcliffe.
I am now 39 and in the last year and a half I have done 4 marathons (PB 3:21) and lots of 10k races (PB 38:46).
I can't say Glucosamine works, as I made 4 changes all at once, but something sure worked very well and I believe they all probably played a part.