Nero 7 caused many users to lose the ability to use their MS Mpeg2 decoder.
And even worse was the even uninstalling did not solve the problem it
created.
There may now be a fix available so check their Website and/or Google for a
solution.

"jz78817" <jz78817@discussions.microsoft.com> wrote in message
news:BED903D1-3C32-4701-8F61-A9CB51273155@microsoft.com...
> it was long enough back where rolling back using System Restore will cause
> me
> a lot more problems. A bunch of other stuff has been installed since then
> and I've since upgraded the graphics card (nvidia to ATi.)
>
> "Graham Hughes" wrote:
>
>> try system restore back to before you installed nero, lots of apps leave
>> loads of legacy stuff in your system which causes trouble, or can remove
>> stuff you do need when uninstalling
>>
>>
>> --
>> Graham Hughes
>> MVP Digital Media
>>
>>
>> "jz78817" <jz78817@discussions.microsoft.com> wrote in message
>> news:731BA1B8-BD0B-4B6F-B0EF-4C10D015C9EF@microsoft.com...
>> > Hi, I'm having serious issues with mpeg2 playback on my system (retail
>> > Vista
>> > Home Premium x64, fully up-to-date.) I first noticed the problem when
>> > Media
>> > Center was not playing the video portion of live TV (I was using a
>> > Hauppauge
>> > PVR card, but swapped in an ATi Theater 550 to test.) Further testing
>> > shows
>> > that anything using the default decoders (i.e. Windows Media Player)
>> > fails
>> > to
>> > play any mpeg2 file- I get audio, but no video. A lot of searching has
>> > led
>> > me to believe that the problem was caused when I installed Nero 7 for a
>> > short
>> > time. I've since uninstalled Nero, but I'm still having the same
>> > problem.
>> > When I try to play an mpeg-2 file in Media Player and look at the file
>> > properties, it tells me that it's using the "MainConcept MPEG Video
>> > Decoder."
>> > I'm assuming this isn't the decoder provided by Microsoft.
>> >
>> > Since Nero has been uninstalled, and there's nothing listed in
>> > "Programs
>> > and
>> > Features" that looks like it would affect that decoder, can anyone tell
>> > me
>> > how I might nuke this (obviously broken) decoder and go back to the
>> > Microsoft-provided one? Media Center is all but useless to me without
>> > this
>> > working.
>> >
>> > Thanks,
>> > Jim
>>
>>
>>