The problem was the now seemingly famous (if you Google it) Apache crash: Parent: child process exited with status 3221225477 -- Restarting. This problem is apparently an access violation.
If you have been unfortunate enough to experience this, and you have read the things about copying DLLs to the windows system32 folder (and maybe checked your PATH environmental variable before you did that!), you might want to read the following snippet from windows.php.net:
Windows users: please mind that we do no longer provide builds created with Visual Studio C++ 6. It is impossible to maintain a high quality and safe build of PHP for Windows using this unmaintained compiler.
For Apache SAPIs (php5_apache2_2.dll), be sure that you use a Visual Studio C++ 9 version of Apache. We recommend the Apache builds as provided by ApacheLounge.
We installed the 2.2.18 build from Apache Lounge, we installed the 5.3.6 build from windows.php.net - and the crashing has now stopped. Lovely Jubbly.