not all sounds play

[somewhereinusa]

I have a problem with sounds, I can play any video file and hear the audio with it, but I can't hear any system sounds,flash or web sites with sound. I can hear the sounds in the speaker test utility that came with the sound card. I can however play a wav file in windows media player.
I'm sure it must be some setting somewhere, but I can't find it.
I not sure if it has always been this way since I built the computer,since I very rarely have  the sound turned on.

[GX1_Man]

Details about the equipment/software could be helpful.

[somewhereinusa]

AMD Athelon 64x2 Dual
XP Home sp2
Realtek AC'97 audio
IE7

[Nancy_O]

Have you looked in Adjust audio properties and is there anything ticked off that shouldn't be?  Have you opened volumn control and made sure mute isnt ticked on any control that shouldn't be??