Audio not working

Hello,

i re-format my pc a week ago and i lost my audio

in control panel its unclickable ,
i mean the audio tabs were all gray and can't click it..

When i check the device manager its look like there's no problem except with the yellow(!) in multimedia audio controller.

In services in CP , the audio was enable and starting , when i tried to install realtek audio ac97 , my pc got blue screen and warned me that if I continue to download my system will not work properly and bsod appears.

pls help me guys , i've try to download atleast 10 drivers vut it doesn't work and they're from the official site

P.S [MY P.C IS HP COMPAQ DC7100 ULTRA SLIM)
help pls!!