all pages 404 ecept for home

Hi,
I am a little new to multisite. My client gave me a new site and all pages are 404ing besdies for the homepage. When I logged into the back, wp was on version 3.5 I think. The version was from 2011. I updated everything, reset the permalinks, and decativated the plugins and tried with another theme, but none of those helped. Please help and if you give me instructions, please make sure the parts that are multisite specific are very clear since I normally only work with reg installs. thanks so much