At 03:41 02/13/08, Nick Northall wrote:
>I recently purchased a new PC running Windows Vista. It has an
>LG DVD burner drive. After 2 weeks it suddenly stopped reading
>CDs but will still read DVDs. The advice from the manufacturer
>is to clear the hard disk and reinstall. This has also been
>suggested by a local PC shop as apparently the registry can
>get corrupted (?). Something to do with Windows losing the
>drivers apparently. Has anyone experienced this ? Anyone got
>a simpler solution ?


Loosing part or complete CD and DVD functionality is apparently
a common problem with Win2k, WinXP, and Vista. (See the MS
article at <http://support.microsoft.com/kb/314060/EN-US/>.)

Here's the Registry fix described in the Microsoft article.
I don't see that you have anything to loose by trying this.
It worked for me. (I couldn't get my DVD and CDRW drives to
read CD discs and the fix restored complete functionality.)
The fix didn't cause any side effects. I've recommended this
to five people and it solved the problem for four of them.

Open Regedit. (I don't have Vista, but in Win2k and Vista
you type regedit into the Start, Run menu and hit Enter.)
In Regedit, navigate to

HKLM\System\CurrentControlSet\Control\Class\{4D36E965-E325-11CE-BFCl-087002BEl0318}

(Note that HKLM is short for HKey_LOCAL_MACHINE.)

In the left pane of the Regedit window, highlite this key by
left clicking on {4D36E965-E325-11CE-BFCl-087002BEl0318}.

(Careful! There are many similarly named keys under
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\. Make
sure you highlite the correct one, the one starting with 4D36E965.)

In the right pane of the regedit viewer you'll find two subkeys
called "UpperFilters" & "LowerFilters". Delete the VALUES for
these subkeys. (For example, right click on "Upperfilters" and
choose "Modify" from the menu that appears. In the small data
window that appears, drag your cursor to highlite everything,
all the numbers and/or letters, and hit the Delete key. (Or
right click on the highlited data and choose "delete".) You
should be left either with nothing, or with 0000. Do the same
thing for "Lowerfilters".)

There may be subkeys with similar names (like UpperFilters_1,
LowerFilters_1, Upperfilters.bak, or LowerFilters.bak). These
are backups. Don't mess with those.

Close Regedit and reboot the computer so that the changes that
you made to the registry take effect. See if your drives can now
read both CD and DVD discs.

Note: The Microsoft article mentioned above suggests that
you DELETE (not just MODIFY) the entire registry entries
"UpperFilters" and "LowerFilters".

If deleting only the values doesn't work, you might as well
go back and completely delete "UpperFilters" and
"LowerFilters". It's similar to what I wrote above.

In regedit, go to

HKLM\System\CurrentControlSet\Control\Class\ and highlite

{4D36E965-E325-11CE-BFCl-087002BEl0318}

Use your mouse to highlite the word "LowerFilters" in the
leftmost column of the right pane of Regedit.

Right click on the name "LowerFilters" to bring up the
small menu with choices Modify, Delete, Rename.

Choose Delete and left click it.

Repeat this for "UpperFilters", choosing "Delete" instead
of "Modify".

My gut feeling is that if the optical drives are present
in Device Manager as working properly (no yellow question
marks), but the drives won't read CD and/or DVD discs,
modifying (zeroing) the upper and lower filter values
should be enough. If the optical drives aren't listed in
Device Manager as working properly, then deleting
UpperFilters and LowerFilters completely is called for.

Regards,
Bill

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