ok wow this is a really old post but hey heres my views on your situation. boot up your realtek hd audio center. this is available via c:\>program files>realtek. once this is booted up set it to start when windows starts and tweak the sound untill you get the best for you. then boot up meia player and go to view>enhancements>and select view enhancements. this brings up a bar at the bottom of media player which you can control equalisers with along with other things. on this bar click the arrow button untill your EQ apears then make sure the EQ's preset is set to the correct music type for what you are listening.
if none of this works then update the drivers for your sound card.
obviousley you have a 3690. so heres a list of what you should have under the device manager list for sound,video and game controllers. just incase something is missing.
legacy audio drivers
legacy video capture devices
media controll devices
realtek high definition audio
now if for some reason one of these is missing then i suggest downloading from some where and reinstalling. for guides to do this i suggest google.
also try downloading tha klite codec pack and install this codec pac allows any file to be played on media player and can help in many ways. it also contains a lot of useful tools.
if none of the above work use the built in recovery utility and use the re-install applications and drivers option. this will put everything right and without wiping all your data. but be sure to back up first just incase something goes wrong.
and i see you run vista did you upgrade to vista from xp before this problem occured if so then that is probbably your problem you need to goto the acer website and download the drivers and utilities for vista. to to this go herehttp://support.acer-euro.com/drivers...k/as_3690.html
and also you should have restored factory settings befor upgrading to vista. as mentioned in the guide on the above page.