Can't log back into site

This appears to be a show stopper. I blindly installed a whole lot of updated modules, captcha-5.x-2.1 being one of them. I normally am logged into the site all the time but today I logged out and was unable to log back in again. www.mywebsite.com/user was blank, as was www.mywebsite.com/?q=user/1 so my lovely website appear to be hosed. A spark of genius struck and I went through all my new modules and one by one disabled each of the 7 or so modules I had upgraded and saw it I could log back in.

Ok, so I shouldn't of done a mass update without testing, my bad, and one can always go to the linux shell and just temporarily rename the module (disable it) and see if that fixes the problem but for the novice user this would be a show stopper.