Minecraft suddenly freezes entire computer

[bwarren97]

This happens quite frequently, and not only do I have to force shutdown, but it corrupts my world to the point where it is no longer recognized by Minecraft. I've tried reducing window size, reducing screen resolution, and terminating unneccecary processes. None of these helped

Here are my system specs:

System:
Microsoft Windows XP Professional Version 2002 Service Pack 2
Computer:
Intel Pentium 4 CPU 2.39 GHz (single-processor), 448 MB of RAM

I also increaced my Page File settings from 1344 MB to 1680 MB maximum, but I'm not sure if it changed anything.