IDE / ATAPI Service Not Starting

A problem has only just occured on my Compaq Proliant 2500 Server. I am running NT4.0 Server SP6a and tonight, I lost access to my IDE devices (in NT only). The IDE CD-ROM (ATAPI 1.2) device is not starting and I don’t know why. I cannot start the service as the server thinks it’s already running (though its not). I recently changed an IRQ for a Yamaha sound card (in the bios settings) but I don’t know what the previous system settings were (or should be)