Realtek HD - Cannot use Sound Effects

Hi all! Newbie here. Can't find a solution to this problem anywhere. Any help would be greatly appreciated. Home Premium 64bit, Realtek HD. No problem with sound until I use Speaker properties or HD Audio Manager to set a sound effect. Then, if I try to play an mp3, WMP 12 gets a "... encountered a problem while playing the file." Other media players, VLC, MPC-HC, etc., act as though they're playing the file but there's no sound. (AND, just for the heck of it I just tried IrfanView and it will play the file and respond to any enhancements I change.) Anyway, the only way I can get the other players to play again is to tick "Disable all sound effects" under the Enhancements tab for the speakers. I'm baffled! Again, any help would be appreciated.

Thanks for the reply, but been there, done that - including two reboots to finish it (and a third to make sure it wasn't going to run again). I actually downloaded Vista, Windows7 Driver (32/64bits) Driver only (ZIP file) and installed from device manager because I found online so many people having problems with the executable. I guess I could try the executable if no other suggestions come about. Thanks again.

Thanks for replying. Yes, I have tried setting enhancements from there (the Realtek HD Audio Mangaer) and from Control Panel Speakers Properties. What it boils down to is that I have to have 'Disable all sound effects' ticked under Speakers Properties or WMP12 gets "... encountered a problem while playing the file" and other players act as though they're playing but there's no sound. Even though I have decent speakers that sounded great on my old XP (VIA Vinyl AC'97) without any enhancement, I'm not getting the expanded sound on my new PC with Realtek so I would like to be able to play with the enhancements - should be able to play with the enhancements - but can't and I can't figure out why not and I don't have that much hair left to pull out. (And how do I insert a smilie here? I've clicked on 'em, double-clicked, quadruple-clicked ...) I've tried every combination of settings I can think of and still no dice. So, I'm open to any other suggestions. Thanks.

Hmmm ... was here starting a new thread and saw this post I made eons ago. I'm going to mark this thread as solved. I solved it by installing a $25 Envy24 sound card that is the equivalent to the onboard audio I had on my XP. Combined with excellent speakers, it sounded great on the XP and just as great on the Windows 7.