Apache keeps crashing with status 3221225477

At completely random intervals and accessing all sorts of pages my
Apache server will crash. It will leave the following in the Event
viewer:

Faulting application httpd.exe, version 2.2.4.0, faulting module
ntdll.dll, version 5.1.2600.2180, fault address 0x00010f29.


And it will put the following line in the Apache error log:

[Mon Feb 19 16:54:15 2007] [notice] Parent: child process exited with
status 3221225477 -- Restarting.

My set up is:
OS: WinXP SP2 (all security updates)
Server: Apache 2.2.4
PHP: 5.2.1
MySql: 5.0

Please can someone explain to me what is going on and give me some
advice on how to fix it. The server ran fine for a few days and then
started having these problems. I can search the web and find lots of
people having the same or very similar problem over the past few years
but I have not found a single explanation as to what is going on or
how to fix it. I have re-installed every part of my set up and have
stripped out everything un-necessary in the conf and ini files but the
problem persists.

Having said that I am still fairly new to this software and it could
very easily be a configuration problem.

All advice is very welcome.

Thank you in advance.

Cheers Mike