Instead of loading nonexistent auctex.el
do
(require 'tex)
which initializes AUCTeX for me (Windows Emacs 24.3 and pdflatex from Cygwin). If you have MiKTeX, you would also need
(require 'tex-mik)
Another potential problem with the package from elpa is the tex-site.el
which is supposed to be generated during installation and contain system-specific data but gets installed from elpa instead. You may want to examine the file and make corrections if needed (and copy it to some other location which is listed earlier in your load-path
). For instance it has some unix paths which make no sense in Windows environment.