D Drive/CD Rom not showing up.

[teej]

Yeah the title says it all. I recently installed another 512mb kingston ddr 2700 memory into my machine and that makes it 1gig of memory. Ever since i did that, my D drive, which was my cd rom drive does not show up. its like its not reading now. The cd rom drive opens and closes but it doesnt read anything that goes into it. Programs that will start up when you put it in the cd rom doesnt even start.(this goes with both of the cd rom drives i have used) I have switched out 2 cd rom drives and the same problem is still there. My whole computer works fine, its just my cd rom drive is not showing up.

Any suggestions?