Spontaneous reboots are usually a power problem.
Now, you would not normally expect an optical drive to draw enough current to pull the PS below threshold, but there may be a short in the power cabling somewhere, or perhaps a power connector is not properly seated.
The optical drive's software driver may also be the cause. If the manufacturer of the drive hasn't promulgated any updates, you might try removing and then re-installing the current driver (Windows device manager can do this).
Thank you - those are great suggestions. I'll move the drive to a spare tap off the power supply and also reload the driver.
The optical drive was on the same power supply cord as another optical drive and a hard drive. I moved it to it's own cable off the power supply and did my best to get it to trip, but so far, all is well. Thanks again for the suggestion.