Alright, stuff is relativly fine and dandy, then BAM. An error.

It doens't happen all the time, but it happens eventually, and is making SP virtually unplayable.

Though it isn't suck a big deal to some of the hardcore MPers, I really like the SP element of most games and want to play it.

I'm in the first block of missions the bottom one, with the tram car.

This is probably well known by now but... (Not bad at all, i just don't know when to say spoilers...)

[spoiler]I'm at the part where you have to go into the tram, then up the lift and open the force field and kill the two guys.

I kill them, then jump on the box and slash open the window to jump out. [/spoilers]

It always freezes here. As well as any other time in the level I try to use the DEMP2 gun. Is it my CD, or something else wrong?

How would I find out what the error is? I can't check the consol cause the game freezes. I could get the one for the 'Would you like to send this information to Microsoft" or whatever message that comes up when ever something closes unexpectantly, but would it do any good?

Maybe a corrupt save. Try playing from a previous save.
Maybe its your comp, turn the graphic settings down and try.
run a dxdiag report and look for errors.
Update graphics cards etc.