When I put a new cd into my drive, I get this dialog box that says:  "d: is not accessible."  Then I go to properties and it tells me that the disc, which is brand new, is 100% full.  Total used space is 100%.  Help.More info is needed.
What OS?
When did this start HAPPENING?
Have you added any new hardware and or software lately ?

patio.  OS=windows xp

no new hardware or software lately.  i did just have the computer defragged, but this is the first time i have TRIED to SAVE to the d: since.  the problem has been going on for a LITTLE while but i had hoped that the defragging would help.Are we talking a dvd or cdrom here, You havnt given alot of DETAILS. Is the drive jumpered correctly and are you sure your clicking on the right drive. The more info you give the more help you can get. Does the drive show up in device manager and if so are there any question marks or does it show up as running ok. What is your drive connected to. Primary slave, secondary master, secondary slave.