Since you mentioned the game is in an ISO file, I can't help but infer that this would be a pirated copy. I'm sorry, but I can't assist you in an effort to do something that's illegal. Doing so would violate the rules here at Tom's.
Back to something I can assist with... the bus speed. Someone must have entered the BIOS and set the FSB incorrectly. That or it's been wrong since the beginning...
You can only access the BIOS when a system is first started, right after it POSTS. You do so by pressing the appropriate key (usually Delete, F2, or F10) when you can see a message similar to, "Press Del to enter Setup." Using the BIOS's load defaults function should revert the system back to automatic detection of the FSB, multiplier, voltages, memory timings, and many other settings. I would try that and only that, because inexperienced people should NOT play around within a PC's BIOS. You can do some serious harm in there with only a couple keystrokes.
I won't be able to be any further help today because I'm finally going to sleep. Hopefully someone else can help you further in my absence.