My website will not load & admin link for site won't either [SOLVED]

This sounds like your 'index.php' file may somehow have become corrupt (maybe through manual editing or your web host unsuccessfully reinstating your site from a backup).

However, this sounds like there is more to the problem.
Even if the 'index.php' file is missing, you should still be able to access the admin section of your site.
(The 'index.php' file is required to display the Showkase home page.)

Try extracting your 'showkase-pro-1.6.1.zip' file (you can download a fresh copy using the link from your purchase email if you need to) and find the 'index.php' file in the root 'showkase' directory.
Use this file to replace the 'index.php' file in on your web server (in your 'htdocs' directory).
If you are in any doubt that your existing 'index.php' file is being overwritten, try deleting it first before uploading the new version in its place.

This may help but as you are not able to access the admin section of your site, I suspect the problem may lie somewhere else.

Try installing and running the Showkase Server Compatibility Test.
Even if you ran the test before installing Showkase, please try again in case your web host has made any changes recently which are affecting Showkase functionality.
If any of the tests fail, it might give us a clue as to the nature of the problem. Also, there are troubleshooting tips in the link above.

Also, please contact your web host to see if they have experienced any problems or have made any changes recently which might somehow be contributing to your problem.
It sounds like there's a chance that there is a problem with PHP on your hosting account. Maybe your web host has changed the PHP version or a PHP setting which is adversely affecting your website.

I hope this points you in the right direction.

You're welcome!
Please let me know how you get on and if you need any further assistance.
Thank you.

Thank you for running the Server Compatibility Test.

The fact that your server has PHP v4.4.9 is almost certainly the cause of the problem. Showkase requires PHP v5.2.0 as a minimum (please see the System Requirements).
It is highly unlikely that you would have been able to setup or run Showkase at all on PHP v4.4.9 so I suspect that the PHP version that is running on your server has recently been downgraded.
You might be able to change the PHP version yourself in your web hosting account's online Control Panel.
Otherwise, please contact your web host and ask them if they can switch you over to PHP v5.2.0 (or later).
PHP v5.2.0 was released on 2 November 2006 so Showkase does not require a super-recent version of PHP but it does require v5.2.0 or later for certain functionality that was released in this version.