I recently took the class offered by the qs where my Janome was bought. I was shown how to use the needle threader...the "trick" is to lift the presser foot, then push the botton that brings the needle up.The needle will then be in the perfect position. It has worked everytime since I learned this....Try it!! I was also told not to use singer needles in the Janome. They are a hair longer and could cause damage to the case....
Hope this helps!
Ditter