Can't log into any of my profiles (even the ones without passwords)

So, I had a bunch of updates I've been neglecting on the app store. So I finally installed them. Only when my computer restarted I was unable to access any of my profiles. I type in the password it accepts it loads for a second and shoots me back to the profile select screen. Same thing happens with my profiles that don't need passwords. Can anyone tell me what's going on? The updates I installed were directly from the apple app store. If it helps I have a late model 2007 MacBook pro with a 17" display.