Pierre Mobian

Might seem far-fetched, but you do confirm you installed the site yourself, and have a full-access admin accounts, with all WP features available ?
Did you customize your functions.php file ?

Do you mean you have access to server logs ? Do they state anything ?
Once *all* plugins are deactivated, the same issue occurs ?

Ok, glad it works; not sure I can further explain, sorry.

Are your database and files correctly set to UTF8 ?
When you try to reach an internal page do you see the URL being redirected to the home page ?
The server log (see you control panel or ask your hosting provider) should show you what happens, either a forwarding (301 code) or more likely a not found page (404) redirecting you to the home, and from that we should know more.

Do you have access to your server logs ? Is this a shared hosting ?
You may try to edit posts again after disabling plugins – all at once, then reactivate them one by one to try and locate the culprit if a plugin causes this.

Your domain is indeed registered (now expires on 25 april 2016 after being renewed on 15 may 2015 so I guess it was initially registered for 2 years in 2013, and was suspended for non-renewal between 25 april 2015 and 15 may 2015).
It is set on DNS by ipage.COM, and is hosted on IP 66.96.147.65 – is this supposed to be your hosting server ? Your hosting provider will tell you.
If the hosting IP is corrected, it may simply be that your hosting space has a default index(.html ?) page generated by your hosting company when an account is created, and that takes precedence over your WordPress index.

Apparently either the propagation occured, or the issue was solved on your host provider end, as the admin console is visible now.
If you’re trying to check if changes on your DNS zones were taken into account, you may use tools such as

https://intodns.com/jvyevelyn.com

WordPress will not keep previous versions, older similar files get overwritten. If you recently made the upgrade you can easily get previous files in your site backup from yourself of your hosting provider, and compare from there.

A blank page is generally linked to an error about which you can find details in your server logs, for example a PHP fatal error (500). See your hosting control panel or hosting support for details.

You’d need to edit the plugin functions probably, but more details on the plugin itself would help – is it provided by www.remarpro.com, or versioned elsewhere by yourself ?

This is one,

https://www.webmonkey.com/2010/02/build_an_ajax_dropdown_menu/

oddly enough not linked from the code D/L page. Enjoy ??

I get the idea and have no doubt it can be done with Ajax but it may require to get down-and-dirty in code ??
Example source : https://duvinci.com/projects/ajax/dropdowns/

I’m not aware of any hack for this, but have developed that for a non-WP site a few years ago. Ajax comes to mind, maybe JQuery would be helpful too.
That site provides examples :
https://www.dhtmlgoodies.com/index.html?page=menuScripts

It seems we are facing the same issue since the upgrade to WP 3.0.4, even though we run dedicated servers and PHP safe mode if off for that site.
From what I see the plugin UAM creates hard-coded image paths into the published articles, hence when the plugin stops working or when you wish to stop using it, you face that issue of images not appearing anymore. We are currently working on a global path update script in order to get rid of those “getfile” URLs, found many times in hundreds of posts on this site. It seems to me the best way to start again without relying on UAM which we don’t need anymore for that site.

Did you modify the dashboard.php file in any way ? The error could be that it simply has extra characters in it, such as a line feed, carriage return or break. You may want to check that in an editor.