O.S. is Windows XP Media Center Edition (same as XP with extras). My Windows Media Player & RealPlayer were working fine until very recently. Now, when I playback known good commercial &/or home movie DVDs using Windows Media Player or RealPlayer, I can hear the audio OK but there is no video. If I playback the same DVDs on the same PC using VLC Media Player, a stand alone Sony DVD player or another PC, both video & audio play OK. When playing back movie files stored on HDD, both W.M.P. & RealPlayer will play both video & audio in AVI files but will not play the video if the file is an MPEG. In trying to troubleshoot this issue, I had a hunch that it might be codecs related. Using another PC (that still plays DVDs OK - with nearly the same software installed) I was able to compare the installed video codecs as shown in the Device Manager. A glaring difference between the two machines was the "no playback" one had an additional codec called fps1. This reminded me that the "non-working" PC had FRAPS software installed which also installs fps1. I thought that uninstalling and manually removing fps1 from the registry & Windows files would fix this but I thought wrong! Although all traces of FRAPS & fps1 were gone, there was still no video during playback. Other than a backup/restore of the out-of-date working system to the non-working one, I'm at a complete loss. If I can avoid doing so, it would save me considerable time. Help! How can I fix this?