I have been developing a new site for several weeks now on 126.96.36.199 on my Windows 7 laptop (with Xampp) and suddenly the admin login page has really minimal styling (mainly a white page). Same goes for the admin section itself: all menu-items appear vertically on a mainly white screen with a Times Roman font. I looks as if it can't load any styling for the admin pages and falls back to minimally styled pages looking like webpages in the early days of html.
The only thing that I did was an upgrade of a Drupal website to the new core version of Drupal. This site is installed in a different folder than the Magento site. I wonder if the can conflict with each other. The Magento site is located in c:\xampp\htdocs\site_a and the Drupal is located in c:\xampp\htdocs\site_b.
The Apache and php logfiles don't give me a clue on the actual reason for this behaviour. I emptied the Magento cache in \site_a\var\cache and \site_a\var\session but to no avail. As far as I can see the permissions on the Windows folders are correct.
By the way: I can access the Magento site itself on my localhost, but changing anything is a hell of a job because of the problem described above. If a run http://localhost/site_a/admin then it shows no admin login page at all. Only if a change localhost to 127.0.0.1 (so http://127.0.0.1/site_a/admin) it shows the admin panel but with minimal styling.
Does this all ring a bell to somebody?
Did you change your urls for admin or skin? Perhaps you minified your CSS/JS?