Dmberry and Hbach -
I recently came across this same exact issue: Windows 7 login screen while booting up but NO login box. Just the "blue background with the wispy stuff" and a pointer. No way around it, not even through Safe Mode. I absolutely could not get access to my desktop, start menu, etc.
I have a Sony VAIO, and I don't know if your computers will be able to do this or if you've already tried it but I thought I would suggest it since it seemed like a miracle to me. I did not have my Recovery Discs and I thought there was going to be no way I could get it to return to factory settings and I'd have to resort to buying the Windows 7 operating system and installing it, even though I should have been able to restore.
I did a live chat with the Sony tech support and they had me hit F10 on bootup which brought me to a screen that would allow me to do a full system recovery. I realize you don't have VAIOs, but I just wonder if you've tried hitting a different key aside from F8 to see if there's any options for your specific computers that have a sort of hidden, built-in recovery system.
Again I realize our computers are different brands but we experienced the same Windows 7 issue, so I thought I would let you know what I was able to do to fix it without the use of a Recovery Disc. It is unfortunately a format and reset to factory settings so you will lose your personal data, but it's better than an inoperable computer.
I hope this helped in some way!