Changed wordpress address

HI,

The site is in folder example.com/main and there is a redirect in the index.php in example.com pointing too example.com/main.
This worked fine until the change below.

1.Mistakenly and for no reason In general settings, the WordPress Address (URL) and Site Address (URL)were changed from examplecom/main to example.com.

2.The site stopped working, no login etc

3.I tried a number of ways to fix it. editing php files, nothing worked and I think I changed all the files back.

4.I managed to get a broken version of the site up by editing the database for the above values.

5. I can see the login box now at example.com but when I login I get a 404 page.

thanks

The blog I need help with is deerparkcentre.com.