after 2.0 upgrade, my serp hits produce a 404

I edited the db connection data in the wp-config file to match my old settings (which included changing db_host from “localhost” to what I had before “my_sql” (who knows why?) even though it said 99% prolly don’t need to change) and uploaded everything to the same dir as before ON TOP OF WHAT I HAD BEFORE because even though I had the db backup plugin activated, it didn’t show on my Manage panel so I was hoping that uploading this way would preserve the db. It apparently did because I can see all my data but the titles are not links as before (although inner story links are). That freaked me out so I checked my permalink settings, they were the same as before, date and time based so then I checked some serps and discovered that none of my previous posts are working and instead are producing 404’s. Any help would be greatly appreciated. TIA