Here is one that might help you? :Ohno:
Dear Dr Margaret
I’ve got a nail-biting habit, and often I don’t know that I’m doing it. How can I stop?
Biting your nails can be a very difficult habit to break, and motivation is the key. You must be really, truly keen to stop. You obviously realize that your habit is off-putting to other people. It also invites medical problems such as swelling and inflammation of your gums (gingivitis), and if you bite the skin at the edge of the nails (cuticles) you may develop painful infections around the nail that can lead to scarring or even loss of the nail. Damage helps wart-causing virus to enter the skin, so you could develop warts round the edge of the nail. Another possible consequence is a herpes infection of the finger, if you bite your nails when you have a cold sore on your lips.
A step-wise approach is the best method of stopping. Ragged nails can be a focus for nail-biting, so the first step is to trim or file off any irregular edge. If your nails are bitten right down, this may not be possible initially, but when the nails start to grow again make sure you keep them well-manicured.
The second step is to work out why you are biting your nails. Here are a few questions to ask yourself.
What was going on in my life when I started to bite my nails?
What emotions make me bite my nails? Are there particular ‘trigger’ situations that make me bite my nails that I might be able to avoid?
What are the situations in which I do not bite my nails?
Is there some problem in my life that is causing stress, which I could sort out? (In fact, this may not help a lot because nail-biting often starts during a period of stress, but then continues as a habit after the stress has been sorted out.)
The third step is to buy some bitter-tasting nail paint from a pharmacy. This is specially made to prevent nail-biting, and you will usually find it in the nail care section of the pharmacy. A scientific study found that this ‘aversion therapy’ works quite well, especially for people who bite their actual nails but not the skin around the nails. For people who bite the skin, painting around the nail does not seem to work, because the bitter substance does not stick to the skin for long enough.
Some people get used to the bitter taste, so the nail paint is not always a permanent cure. You could then try the fourth step, the ‘competing response / habit reversal’ method. This simply means that whenever you feel the urge to bite your nails, you do another action instead. For example, you could wear an elastic wrist-band, and snap it on the inside of your wrist whenever you feel the urge to bite your nails. Alternatively, clench your fists tightly with the thumbs inside against the palms of your hands for a minute or two; if you are in a situation where this action would be inappropriate, you grasp some object instead. Scientific studies have shown that this method can be surprisingly effective both for nail-biting and for nibbling of the skin around the nail.
For this method to work, you must train yourself to know when you are biting your nails, which can be difficult. Ask your friends and family to help by immediately telling you whenever they see you nail-biting.
You can take comfort from the fact that a lot of people are struggling with this habit. More than 6% of students say they have a nail-biting problem. After seeing close-ups of himself in The Return of the King, Elijah Wood (who played Frodo Baggins), announced he would stop biting his nails, having been a nail-biter since childhood. Britney Spears and UK Chancellor Gordon Brown are also said to be nail biters.
Sources of information
Ballinger BR. The prevalence of nail-biting in normal and abnormal populations. British Journal of Psychiatry 1970;117:445–6.
Silber KP, Haynes CE. Treating nail-biting: a comparative analysis of mild aversion therapy and competing response therapies. Behaviour Research and Therapy 1992;30:15–22.
Twohig MP, Woods DW, Marcks BA, Teng EJ. Evaluating the efficacy of habit reversal: comparison with a placebo control. Journal of Clinical Psychiatry 2003;64:40–8
Hope it might help you. Keep strong positive!
just be glad!!! lol
okay, no problem 
I think I'll pass on that one hon......