CHMOD Settings Problem?

I've been asked to maintain a friend's website that she was previously creating/maintaining with FrontPage. She gave me the login information for the website, and I've been able to access the files through SmartFTP. I'm able to download files and make changes to them (using another WYSIWYG HTML editor), but when I upload them and try to view them by typing in the URL in a web browser, the page comes up blank.

I thought maybe this had something to do with the CHMOD settings, so I tried resetting them to various combinations, but either the same thing happens (completely blank page) or I get the 403 Forbidden error. I'm not sure what settings I need to use to be able to have my edited HTML files show up.

Any suggestions would be greatly appreciated!