cannot find hardware device

I have a dvd burner & a dvd drive. Both have been working
fine since I installed them over a year ago. I was
uninstaling
some unused programs, and now these two drives can not be
found. They don't show in my computer. When I checked the
device manager the drivers show up, but they have an ! in
front of them. When I click on the driver it is loaded
but can not find the hardware device code 41. When I
reboot the lights on the drives light up to show that
they are working. I have up pluged them and rebooted shut
down pluged them back in rebooted again. I get a new
hardware device detetced massage, but they still don't
show. please help!!! Thanks Wayne