Halp! I have a chop-shop computer running two older graphics cards in tandem (dont ask how, friend built it) and can play fallout 3 on med graphics. However, upon choosing dx9 option for resident evil 5 and trying to play, it gives me a loading screen that ends with a computer reboot. When it comes back to life, I get a 'critical windows error' (within windows, boots nominally). The computer is pushing windows xp and is otherwise stable in performance. Also to note; none of the lights (processing or dvdrom) even flicker as it resets. Im sure it WOULD work on minimum graphics settings... um... help?
Interestingly I couldn't get this to work instantly for me either and my computer is of a plenty suitable spec. Try logging into the Administrator account of your PC and loading the game up then. If the Admin account is not displayed, download TweakUI for XP, a quick google search will help you find this, then the Logon Tab within TweakUI "Show Adminstrator account on welcome screen". Or somdething incredibly similar. See if the game will at last load then. If it does, try changing the settings then and quite the game. Reboot, then see if it will load under your usual User Account. Let me know how it goes.
I just found that the graphics engine in the game supports every NVidia Graphics card from 6800 up except for the 7300 series... guess which videocards I have... srry for the late reply but thanks for trying.