Hi Squire, You will get there in the end...You have done well thus far... The new nut can be causing the buzzing by being incorrect depth.
Removing the Nut
If you look at a variety of instruments you will find that the shape of the nut and the way it is mounted on the neck will vary. Ideally, nuts are held in place by a small dab of glue, preferably white glue, Titebond or Hide glue. In the world of instrument repair we must keep in mind that instruments are built to allow for disassembly, so, if yours manages to pop loose a small dab of Elmers or PVA glue will be sufficient. The use of superglue, epoxy and other inappropriate adhesives have given luthiers nightmares for years and should be avoided.
While removing a nut is
a very simple matter
there are a few which can make removal a bit of a challenge.
Removing the nut?
When the instruments nut is not sitting in a channel or "inlayed" it is often possible to give it a light tap to dislodge it.From Fretboard side or side on. (Use a plastic head hammer or a piece of wood as thick and as wide as the nut to tap against it) After scoring or removing finish to prevent chipping as mentioned use a block that equals or exceeds the width of the nut in order to pop it loose with a gentle tap of the hammer.
However, other things can make removal more challenging. When the nut has been painted over it first has to be scored to prevent chipping finish on the neck .
And if the nut has been secured with an epoxy or other strong adhesive extreme caution should be used as they are likely to pull up some wood with them.
Nuts that are "inlayed" or set into a channel require more caution and a different technique. Tapping one of these nuts forward to dislodge it could spell big trouble. Damage to the peghead veneer can result if one is not cautious.
Removing an "inlayed nut
" When the nut has been tightly seated in a deep channel and then finished over caution and patience is necessary for a clean, flawless removal. There are several options when removing an inlayed nut but I do not recommend those with little patience or skill attempt removal as damage to the neck, peghead veneer and/or finish can result.
Before attempting removal the finish over the nut should be scored and removed to prevent finish chip. Some inlayed nuts can be lifted up and out of the slot using flattened end nippers or a similar tool, a few nuts can be loosened by tapping sideways and still others seem as though they are holding on for dear life and can only be removed by destorying or, when suitable, cutting a very thin kerf (.008 or so) from the front of the nut (between the nut and peghead) to create a gap which makes removal possible.
Securing a Loose Nut
As I mentioned before, if the nut on your instrument should manage to pop loose you can use Elmers or wood glue to reattach it. The use of permanent adhesives can create problems should the nut need to be removed for future repairs.
Here also are a couple of links for extra info and pics.
http://www.youtube.com/watch?v=pxcwhUhq61c (Video)
Regards Fenderphil
http://www.ehow.com/how_4683806_replace-guitar-
nut.html