[danielh112768]

For Audio problems: Open QuickTime Player and go to 'Edit' -> 'Preferences' -> 'QuickTime Preferences' -> 'Audio' then under 'Devices' click on 'Select Audio Playback and Recording Devices'. My default device is Realtek AC'97. Try it. Google that name and download. See if the 'Device' field is populated after download and install. If so your sound should work.

Else, right click on My computer go to Properties -> Hardware -> Device Manager. then click on the + next to Sound .. Highlight each device, right click and select update drivers. If this doesnt work for you I am sorry. I hope I was helpful.


For Video problems: Open QuickTime Player and go to 'Edit' -> 'Preferences' -> 'QuickTime Preferences' -> 'File Types' -- check here to see if the file format of your problem video files is selected.