What could be making the bathroom sink hot knob keep turning? We can turn water off if it's pushed just right but other than that it would do 360's all day long.

No leaking beside drips from faucet when valve knob isn't in the exact spot, where it should stop.
Never done plumbing/faucets except toilets.

I need advice on what the problem could be!!!

Took handle off and nothing but a little crud and under the sink same thing, square washer is a bit off compared to the cold valve.

Ideas? Please!

 

It's pretty hard to help you without at least a little help from you.
What is the manufacturer of the fixture ?
Is this a new or old fixture ?

Is it possible to take a picture of it and post it here ?

 

Here is a picture of the faucet. Thanks!