After installing Fallout 3 for the first time, I played for a little while and found it quite fun. Up until around the 10th birthday whereupon my computer crashed.

I attempted to reboot, but as the boot-up messages began, it got to a point where it said "IDE CHannel 1 Slave... Not Detected" and the boot-up would immediately fail. I even tried starting it up in safe mode and nothing happened.

Does anyone know how I might be able to fix this?

(I know Oblivion worked on the computer before so I don't know why Fallout is giving me a problem...)

Did you try reseating the connections to the slave drive? Power and data?