My dvd-rw can't read dvd but can read cd

1.Turn on the PC. When the HP/Compaq logo screen appears, press the F1 key repeatedly until the BIOS Setup screen appears (on some models this key press may different, F2 or Del)
2.Use the Left and Right Arrow keys to select Main.
3.The hardware-identifying name should appear next to Secondary Master, Secondary Slave, or Primary Slave.
If the name for the drive exists, skip to Step 3. Otherwise, continue to the next step.
Step 2: Reseating cables

If a drive name does not appear for each drive and None is listed in the BIOS, use these steps to open the computer case and reseat the drive cables. Work on a hard flat surface over a non-carpeted floor.

1.Turn off the computer, unplug all cords from the PC, and then press the Power button on the front of the PC for five seconds.
2.Remove the side panel.
3.Remove both the IDE ribbon cable and the power cable from the back of the CD drive.
•If the drive name appears in the Primary IDE section or the hard drive name is now missing, the IDE cable is bad or the drive settings are wrong. Replace the IDE cable and connect it according to the drive jumper settings . That is, if the small rectangular connector (the jumper) on the drive is set to MS (Master), connect the master end of the IDE cable into the back of the drive. If the jumper is set to SL (Slave), use the slave connector on the cable. If the drive is set to CS (Cable Select), you can connect using either connector on the cable.

Step 3: Removing Drive in Device Manager
Remove the drive name from Device Manager:
4.Close the Properties window and select the CD drive name.
5.Click the Uninstall or Remove button (in Windows XP this is the square button with a red X).
6.Click Yes or OK to remove the CD listing. Do not restart the PC.
7.Close Device Manager.
8.If your PC has Windows XP, perform the next step to clear the registry filters without restarting the PC.
Clearing the registry filters in XP
Click Start, Run, and type the following into the Open field: regedit
Click OK. The registry editor appears.
In Windows XP, click File, Export, type a filename that is easy for you to remember, and click Save.
In Windows 2000, click Registry, Export Registry File, type a filename that's easy for you to remember, and click Save.
A copy of the registry has saved for back-up purposes.

Click the plus sign (+) next to the following items in the list:
•HKEY_LOCAL_MACHINE
•SYSTEM
•CurrentControlSet (or the current control set with lowest number if that is all that is listed)
•Control
•Class
Select 4D36E965-E325-11CE-BFC1-08002BE10318.
Select UpperFilter in the right window and press the Delete key.
Confirm the deletion by clicking Yes.
Select LowerFilters in the right window and press the Delete key.
Confirm the deletion by clicking Yes.
Delete all other UpperFilter and LowerFilter values within the 4D36E965-E325-11CE-BFC1-08002BE10318 key.