Its a bit worrying that its not detected in the BIOS - have you been playing around
inside the machine recently? Perhaps its more a loose IDE cable issue rather than a bad driver causing the problems.
What if windows does not re-detect it? Am I screwed?
In the
worse case scenario you'll have to sell your house and give up your job but I wouldn't call that screwed

Nah, only kiddin' - It wouldn't really cause any big problems - if its working Windows
will redetect it, if its not working then you are no worse position anyway.
My advice would be...
1). Take case off your machine and check the IDE cable coming from your CDROM/ZIP is still connected to the motherboard.
2). If that doesn't solve the problem delete the controller from device manager and let Windows redetect it.
LMK how you get on. Good luck!
Edit : Just re-read your original post and you say that the Zip drive is detected in the BIOS, so therefore the IDE cable must be connected correctly to the motherboard - make sure the IDE cable and power cable are firmly inserted to the back of the CDROM