After migration meu not working

I just migrated my WP site from a sub-folder to the root folder of my website. The home page comes up fine with all the graphics links. I can access the CP panel and everything there looks as I expect it to.
However on the site, none of the menu links work (which all happen to be pages, no categories with posts). At first I had the permalinks set to date and name. I tried changing this to the default, but the menu links still don’t work. I noticed with the default setting on, if I go to an Edit page and click: VIEW PAGE, then that page does load correctly. But if i then go back to the Home page and reload, then click a menu link,I still get a 404, and i can see the menu link was trying to load the page as if the -date and name- permalink option were still on.
What is also strange is that I have another WP blog set-up in a subfolder on this site that is still working just fine, and it is using the permalinks option: date and name.
Other info: the site is on a Unix server. The host:YAHOO (I’m trying to get my client to ditch them) does not support .htacess files. I contacted them and they couldn’t tell me what file WP would be using instead.