if it finds it, yes, it *should*, but please keep in mind, I am going off of what I have read in other forms. Generaly, it would only find it if it was installed by a previous verson of slayers (I.E. 2.5 or <). If it doesnt, then I would suggest to use the file manadger when booted with slayers, and delete the old evox manually, then use the install/upgrade feature of it.
but, please, please, for the love of god please, keep in mind that I never used slayers before, I am basing this off of memory from what I have read, so I may be wrong about this. if you do decide to do this, back up AT LEAST[U] the C:\ partition (when you boot with slayers, you still will have ftp access) be for you do anything so if something goes wrong, you have the C:\ ready to be put back into place.