Alright, I'm extremely frustrated. I've always been able to fix computer issues I may be experiencing at any one time, but for the life of me I cannot figure what is causing the windows audio scheme sounds and internet sound to not play. Windows media player can play songs fine. Speakers play the sound. So will winamp and all other media devices on my computer. Everything works fine except for windows audio scheme and internet sound.
I've uninstalled and reinstalled macromedia flash player. I've tried uninstalling/reinstalling my entire OS. I've tried updating the audio codecs/drivers for my onboard sound card. I've tried doing a repair installation of windows xp pro (my os). I've tried removing all malware, adware, pups ect. I've gone into the registry and edited the wavemapper string value with the help of one of my techy friends. I've tried updating windows with everything they offer for audio. I've downloaded updates from my motherboards manufacturers site (asus M2N-E). I've checked to see if there are any hardware conflicts or any problems w/ software. I've tried downloading other audio filter programs and other audio codecs. Nothing to this point has worked. I would greatly appreciate any help that anyone out there could give me. I know alot of other people out there have this problem because I've read many forums, but none of the solutions that have worked for others have worked for me. If anyone out there can help me I would really really appreciate it.

Control Panel -> Sounds and Audio Devices -> Audio tab. Is this set to the right sound card or is it set to (typically) a modem?

I double checked just to make sure it wasn't something so simple and no, it was set to my default sound device which is Soundmax HD Audio. Its set for both playback and audio recording.

It is unusual for sounds to play in everything else but Windows itself. Usually it plays sounds in everything or it doesn't play anything at all in any program.

Try resetting your sound scheme to the default for, well, lack of any other ideas really.
Also do Start -> Run -> type in "msconfig" (no quotes) -> Startup Tab and click Disable All. Then OK and restart. Now see what happens. If the problem is fixed, then the issue's being caused by something running on startup so enable programs again until you find out which one it is.

still no sound

ok, on top of my computer tower I have a headphone port for my onboard sound card and the sound for internet and windows comes out through that...but mp3 sounds come out through the speakers pluged into the back of the motherboard... I checked my motherboard manual to check for the recommended default settings and everything is set to default and it was set to recomended. I checked the motherboards manufacturer website for information about any conflicts in bios for this but they have nothing and I checked the soundmax HD audio manufacturer for information on this and they have nothing. any suggestions?? this is a really wierd problem. I've looked through the huge bible for windows xp and no solutions there either.