Pulled this from Techspot.com... 
http://www.techspot.com/vb/topic31748.html  about halfway down the page.  I 
have used this recently and it works.  Try a bootable CD or DVD such as a 
Windows install disk to verify that drives are reading before Windows boots. 
HTH
Mark
If your drive reads cd's, but not dvd's That indicates that the hardware 
works fine. You will need to edit the registry inorder to fix this problem.

1) click the start menu
2) click on "run"
3) type "regedit" and click ok
4) go to string key 
"HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E9 
65-E325-11CE-BFC1-08002BE10318}
5) delete "upper filters" and "lower filters in the right side window.
6) right click my computer in the start menu.
7) click properties
8) go to the hardware tab
9) click device manager
10) expand the dvd/cdrom drives
11) right click the dvd rom and click uninstall
12) restart computer

after restarting, windows should automatically install a clean ROM drive and 
it should read DVDs just fine if you have the correct DVD decoders.
----- Original Message ----- 
From: "Larry Scroggs" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, November 23, 2007 4:07 PM
Subject: [PCBUILD] CD/DVD drives not reading disks


> System specs are:
>  Homebuilt system (September 2005)
>  Windows XP Pro SP2 with all updates
>  Motherboard : MSI K8N Neo4/SLI (MS-7100)
> AMD Athlon(tm) 64 Processor 4000+
>  2 GB RAM
>  320 GB Seagate SATA HD (C)
>  250 GB Western Digital ATA HD (K)
>  PLEXTOR DVDR   PX-716AL  (D)
>  PLEXTOR DVDR   PX-740A  (E)
>
>  System was working fine up until a month ago. Now various CDs and DVD 
> disks are not read in either CD/DVD drive. When data, music, or video 
> disks are placed in (D) (slot loading) drive, drive light flashes for 
> approx three seconds and the disk is ejected. When the same disks are 
> placed in (E) drive (tray loading), the drive light flashes for approx 
> eight seconds and then stops.
>
>  Both drives show up in the BIOS. Both drives show up in Device Manager 
> and are shown as working properly. Both drives show up in My Computer.
>
>  I have tried tightening the connections then removing and replacing the 
> cable connecting both drives to the MB. I tried uninstalling the drivers 
> in Device Manager and letting Windows reinstall upon a reboot. I updated 
> the firmware for the devices from the Plextor website. All to no avail.
>
>  My research on the Web has lead me to believe that this problem has come 
> about by a problem in the Windows XP registry. Perhaps some software I 
> uninstalled removed the registry entry that controls my CD/DVD drives? I 
> even downloaded a registry tweak I found at a Windows help forum and 
> incorporated it into my registry but that didn't help either.
>
>  Do any of you have some ideas I can try out? Thanks for any help you can 
> supply.
>
>  Larry Scroggs
>  El Paso, Texas, USA
>
>              The NOSPIN Group is now offering Free PC Tech
>                     support at our newest website:
>                          http://freepctech.com
>
>
> -- 
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> 11/23/2007 9:19 AM
>
> 

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