we dont know what your D drive is. is it your cd rom? is it the 2nd partition on your hard disk? Is it an eternal hard disk? who knows.
To help us assist you, please provide more information:
1) Decribe the issue you are having in detail. For example if its with a specific piece of equipment, include the make and model.
2) When was it last working normally? Since then, did you add/remove any software or hardware?
3) What steps have you already tried to resolve the problem? (rebooted, searched google, etc)