A Pentium 4 machine with 2 GB RAM and a Geforce 400 is at this point in time "low end" especially for a 2008 edition of Maya and many of the other programs involved in making a movie. And with 13.6 GB of hard drive space total, I don't know if you'll even have space to render everything out and comp it (wouldn't particle caches pretty much eat right through that?). I think the Maya help covers particle caching and to be honest, I'm surprised your just "occasionally" running into these issues.

The reason why its crashing when you batch via Maya is because your system has to 1. run the OS 2. Run Maya and 3. Run the batch process, and with such limited resources something is going to buckle. And your interactive viewing is slow because the video card isn't up to the task.

I don't know but I wouldn't waste time comparing what hardware these studios use (as they've invested thousands upon thousands of dollars in that alone) to that of what one guy who is trying to get his animating on, its always good to know but that's about it. It's time for a new machine with a decent processor and as Steve said, a 64 bit OS and 8 GB RAM. Oh yeah, and a 500 GB hard drive is a good start.