Sherlock

I appreciate your positive response but evidence suggests that ImgBurn affects something?To have the same symptoms twice in succession may not be conclusive but it certainly indicates a link?

Imgburn 2.5.1 Installed last week to burn a HDD based compiled (personal) DVD. Did the job fine but I couldn't watch with either Windows Media Player 11 or PowerDVD. WMP just says "Unknown DVD" and PowerDVD plays sound only with swirly patterns on the screen. So, after checking I still had all the codecs installed I went back to a pre-ImgBurn-installed HDD and WMP, etc., worked fine. So I installed ImgBurn to burn another copy of my DVD. Burned the DVD and now will only play with VLC - same as last week. The conclusion seems to be that ImgBurn trashed some setting which prevents WMP & PowerDVD accessing the codecs. Same problem even after uninstalling ImgBurn. BTW - I did reinstall WMP 11 and repaired Win XP SP3 just in case.