2.40 crash during animation render

system : windows xp intel 4 2.4 ghz hyperthreading (on) 512 ram
during animation render: blender renders nearly the whole animation
then suddenly it crashes in such a way as i cant even look at dos console (or whatever its called) to see what went wrong.
all i know is that it happens whenever the threads button is on. (which works on my 2.37a blender) and when im using different osa filters,
filters im positive it happens on are catmull-rom ,mitchell-natrevelli,tentm,
im certain it crashes on these, i think it crashes on them all tho (ive run so many tests trying to figure it out im a little cunfused about the others)
anyway if you dont have the threads button on it renders normally.

i did all the uninstall everything …reinstall everything and even downloaded it again, nothing stops it.(that i know of)

also as a side note during some animations i have seen what looks like the faces flickering very rapidly and some light bursts where there are no lights. right now i still can get it to happen reliably tho so i dont know what that might be…(this is seperate from the animation crash thing.)

Does anyone know what this is caused by or how to stop it ??