videos not playing as insta buttons

[zilda]

Hya Roy
thanks for the prompt reply.

the audio card is set on windows default as stated in manual.

i have checked what you requested and found them set to preferred

if i start hoster first thing all insta button mp4 videos play not a problem every time.
however if i play a mp3 audi quip on insta button this also plays first time but if i then try to play a video after an audio file the video is graphics only.
if I then make hoster play the relevant video in hoster playlist it plays not a problem (on one screen as normal) if i then abort it half way through and instantly click on relevant insta button with same video it plays fine audio and graphics and all other mp4 videos play fully ok
the fault only appears after playing an mp3 audio clip on insta buttons.

when the fault is on if i look at volume mixer only application shows audio levels see attached picture