Turn off plugin without dashboard access

I managed to kill my site a little by deleting the /wordpress part of the address in settings.

I found out how to put that back but now every time I try to get to the site it tries to redirect me and I can’t see anything other than an unformatted page.

Is there a way to disable the plugin from the server by editing a php file so that I can get the site back to normal and then reinstall it afterwards?

http://wordpress.org/extend/plugins/redirection/