I'm not running a multicore processor so I don't know what's causing it.
It wouldn't be a big deal if the save points weren't so far between, last night there was this long puzzle with multiple parts to figure out and I spent quite a while on it, when I was almost done the game crashed and I found I had to go through 2 cutscenes, long walking distance and a lot of fighting to solve that puzzle all over again.

Any ideas how to make this game crash less often?

It shouldn't be crashing at all.

Are you using a processor with Hyper-Threading by any chance? The problem is not exclusive to physical cores.

Well it's a Pentium 4 with 3 Ghz, I have no idea if it has hyperthreading, how do I find out?

They easiest way is to see whether there is a HT sticker somewhere ;-).
I'm not entirely sure how Windows handles these, but common sense says that task manager should still display all logical cores, so if you see two graphs - that's HT.
For definite answer check "processors" field in Device Manager.

Yeah I see 2 graphs, guess it's hyperthreading.

I look up the solutions, thanks

See the sticky thread for details.