PHP no longer installed?

My client's php pages have not worked since sometime after Friday 2/13. When we try to connect to them, we get the error:
~~~~~~~~~~~
Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, (me) and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
~~~~~~~~~~~

Research leads me to believe PHP is no longer installed on the server the site is on! (Don't know if the site was moved to a different server, or if PHP was removed from the server they are on. Either way, the client was not told of any changes, and has made no changes on their end.)

When my client contacted CS they received this reply:
~~~~~~~~~~~~~
It looks like your site uses a custom PHP install. Since you`ve recently moved servers, your old custom PHP install no longer functions properly.
If you take the same steps as you did before, to create a new custom PHP install, your site should start to work again.
~~~~~~~~~~~~~

This is not a custom install of PHP, and the client did not "move servers" (as far as they know!).

I wrote the PHP pages myself, starting March 2008, and at that time the PHP installation that was already there and available was version 4.4.8 (I have a phpinfo report from that time.)

CS has not responded to messages I have sent.

Can anyone shed any light on what happened -- and, more importantly, how I can get my client's site working again?

Do you have a .htaccess file? If so, then there shouldn't be any mention of php in it.

Have you tried a real simple php file such as:
<?php
echo phpinfo();
echo "\n";
?>

Customers do get moved to other servers from time to time. If they really did get moved to another server, it's quite possible that PHP4 is no longer supported on the new servers. I can't remember if there was mention of that or not. If you go to the panel for Domains -> Manage Domains and click Edit for that Fully Hosted domain, is the PHP4/PHP5 dropdown menu still at the top?

-Scott

Thank you, Scott!

I just heard from the more "server technical" person who has also been working on the problem. He called in a recruit, and the two of them figured out that there was a corrupted file in the DreamHost PHP installation. That was fixed, and my client's site is now working just fine.

FWIW, I just checked & do not see any PHP options when I edit that domain in "manage domains".

For the record, I also learned that:
1) The client WAS messaged by DH on 2/16 that their site was moved. Either that message did not reach them, or (because it indicated that there should be no noticeable difference) it was not remembered when the site started failing.
2) My inquiries to CS at DH apparently were not received, so that's why I did not receive replies. They do not show up in the (very useful!) support log available on the control panel. Perhaps they did not get through because I was forwarding messages that had been forwarded to me? Dunno. Live & learn. I would have thought e-mails addressed to support@... and including a support ticket number would have reached *somebody*, but I guess not!
3) The tech person did not receive a reply to his 2/17 question until this morning (2/19) and that's when HE learned the site had been moved to a different server.

All set now. Thanks again!

The PHP options are only on old domains back from when there was a choice between 4 and 5.

1) Well, interesting, but apparently not the source of the problem. Glad it's fixed.

2) Email to customer support isn't always the best way to go. I don't know how their software parses support email, but it seems to be a bit picky. It's great on open cases for ongoing dialogue between original parties.

-Scott