In reply to tjin:
KT tape can be used to cause the VMO to fire earlier in some of the taping techniques, but it doesn't fix the knee or pull the patella over etc like the old fashioned McConnell taping method. As said above, for knees, the jury is out as to its benefit, although in other areas there is a better standard of evidence for efficacy.
I have used it on long runs during recovery from PFPS and I would say it does reduce pain. Different types can be quite different in elasticity and tension. If you put on a few layers it does get more rigid. One physio loved it, most were much more equivocal. Remember, if you use it, you will have to live with that shaved knee look which is a bit bizarre.
Since most knee problems seem be exacerbated by the upper thigh muscles and the foot/calf a good physio is the answer for you, and perhaps looking at your running technique (I find James Dunne very informative and have been to one of his workshops with some benefits
http://www.kinetic-revolution.com )
Post edited at 16:18