prestashop issues

I've tried all of the tricks I can find on the forums so far. It was working fine about 2 weeks ago and then it just wasn't one day. No module installs or upgrades, no changes at all that I did and other than my web hosting, I'm the only one who has access. I haven't been able to figure it out. At this point, If I can't find a fix, I might try to do a Prestashop upgrade.(not the 1-click upgrade as this has already killed my site once!) Any help before I try this though would be greatly appreciated.

Oh, and during one of my attempts to fix this, I had to recover my website from a full backup. After this, the contact us page still doesn't work and now my forums page is giving a 404 error that I can't figure out.

Also, I've tried turning on debug mode for the contact us page issue and no errors are shown.

can you guys help me?  what would be the cost?