error 39 on Vista laptop

I bought a new HP Presario CQ50-139WM just four days ago. After accidentally letting the battery run down and the computer went dead, I found I can't access the CD drive. When checking the device manager, I get "Windows cannot load the device driver for this hardware. The driver may be corrupted or missing. (Code 39)"
I've tried a system restore from several hours before the incident. This didn't work. My limited knowledge of this kind of thing is now used up and I could use some help.

Thanks,

Dave