Apparently this is a fairly common problem. I did a search on your 
complete error message and came up with a bunch of hits. I believe your 
problem is caused by not having a required decoder to play videos off of 
you DVD. Of the numerous hits the following seems most helpful and in 
plain English:
http://www.tomshardware.com/forum/101755-45-decoder-windows-media-player

I hope this helps.

Tom

Joyce A wrote:
> If that were the case, would I be able to view still pictures?  (I 
> can...  It reads still photos on CD and DVD just fine!)  How would I 
> test that?  Just replace the CD/DVD drive?  (Easy enough to do, even 
> for a non-tech ol' gal like me!)
>
> The error message I keep getting is "Windows Media Player cannot play 
> the DVD because a compatible DVD decoder is not installed on your 
> computer" -- which of course lead me to believe that it was a software 
> problem but Russ asked me to post the problem here.  I've asked in 
> various forums and I've asked Microshaft, uh, _-soft_ <ducking and 
> grinning>; I've haven't even come close to a solution as yet, besides 
> replacing the drive.  I'm not exactly holding my breath to hear back 
> from Microshaft either...
>
> Yes, there used to be a partition, behind which was all the backup 
> Windoze stuff...
> Joyce in SE Ohio
>
> Hugh Vandervoort wrote:
>> Your DVD laser has probably died.. This is pretty common. These drives
>> are cheap and easy to replace.
>> The drive letter change suggests there was a partition on your C drive
>> that is no longer there. These partitions are common on many PCs.
>> If you have a Phillips screwdriver and a little patience we can help
>> you with this.
>> There is an excellent guide here:
>> http://freepctech.com/pc/001/installing_ide_devices.shtml
>>
>> On Sun, Jun 7, 2009 at 4:03 PM, Joyce E <j3e@...> wrote:
>>  
>>> I used to be able to view a movie or other video DVD on my PC, running
>>> Windows XP SP 2.   
>
>               
>

            Do you want to signoff PCBUILD or just change to
                    Digest mode - visit our web site:
                   http://freepctech.com/pcbuild.shtml