My audio stopped working

[axis_d]

I'm having a weird problem. Out of nowhere my audio just stopped working completely, I dont know if some drivers got corrupted or something, but I need to figure out whats wrong. I figured maybe somoene here would have some suggestions on steps I could take to solve it.
Its a store bought del p4 1.g ghz computer, I dont even know what kind of sound card it has. When the sound stopped working, also, for some reason anything that played using windows media player turned into one of those icons where you have to choose what program you want to open with. WheN i chose windows media player, (or any other program) it wouldn't play, so i figured maybe I needed to re-install windows media. So i did that, and now videos play, but still no sound. when I try to play a sound file with windows media, it says something to the effect of, "Can not play file because there is a problem with your sound device. There may not be a sound device installed, or it may be being used by another program". I ended all programs, but still nothing. I tried going to the control panel, and went to "Sounds and Multimedia", but when i tried playing some of the default windows noises, like the asterisk for example, it gave me this message:

Windows can not play the file. the File may be damaged or use an unrecognized compression format. To resolve this issue, replace the file, or use Add/Remove programs in control panel to install Audio Compression.

i'm not sure what that means exactly but if someone could help I'd appreciate it. Thanks very much for the help.

[Alienware_Dude]

Go into the Device Manager and look for yellow exclamation marks. You need to re-install your sound drivers.

[axis_d]

hey..well I went to the device manager, and it had an exclamation point near the Santa Cruz Turtle beach software. but when I clicked on "update drivers" it said I already have the most current drivers installed. any other ideas?

[Alienware_Dude]

Go to the Device Manager and Uninstall the drivers for the sound card. Reboot.