BleepingComputer.com: Sound not working

Hiya! Alright, getting to the problem right away, the sound on my computer hasn't been working for about a week now. I've been trying to find a way to fix this for hours at a time every day but nothing has been working. There's a red x over my speaker icon which is how I first came to notice the problem. When I opened my volume mixer to see if I had put the volume on mute, it told me that there was no audio device installed. I have installed a new audio driver, realtek high definition audio. When I hover my mouse over the speakers it now says 'Volume:0' and the icon still has that red x. I tried setting the speakers to default as I've heard you're supposed to do but the button is grayed out. I don't know what to do!! Any help would be wonderful! Thank you so much ahead of time if you can help me fix this problem!

Your audio is probably corrupt
What is the make and model number of your computer or sound card?

The model number is a1720n. Does that help at all?

HP Pavilion a1720n Desktop PC
Download:
Original audio driver
Realtek High Definition Audio Driver

http://h10025.www1.hp.com/ewfrf/wc/softwar...228&os=2093

audio driver Update
Supposed to help a noise issue

http://h10025.www1.hp.com/ewfrf/wc/softwar...228&os=2093