keyboard & mouse lockup after disk eject from dvd or cdrw drives

I have a dell dimension 4550 with Win XP SP2 that recently develop this

problem. After playing or writing to a disk in either of my dvd or cd drives

then ejecting the disk, my keyboard or mouse will not function. It seems the

system locks-up. The only way I can get the system to work again is to pull

the power cable and reboot. After I reboot, everything works fine until I use

the drives again. And then I have the same problem. I don't know where to

start troubleshooting this problem -- thanks for any help.

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A intermediate computer student