No sound on Windows.

Not so long ago I installed new Windows Vista updates and after PC restarted there was no sound. I tried installing new drivers, reinstalling windows, installing windows 7, but nothing helps. So i thought maybe it's a hardware problem. I installed ubuntu just to make sure and guess what sound works perfectly. By the way sound device is enabled and speakers are ok. The only problem seems to be that Realtek HD audio manager doesn't recognize any input or output it shows that nothing is plugged-in.

Processor: AMD Phenom(tm) 9950 Quad-Core Processor (4 CPUs), ~2.6GHz
Memory: 8192MB RAM
Motherboard: Gigabyte GA-MA78G-DS3H
VGA: ATI Radeon HD 4870 X2

Thank you.

Your board has the (pretty much standard) RealTek ALC889A audio CODEC - try D/Ling the drivers from here:
http://www.realtek.com.tw/DOWNLOAD [...] Down=false
and istalling them - perhaps an MS 'upgrade' is broken...

Hmm - wierd, the 'two OSs test' pretty much eliminates actual harware problems; is device manager 'complaining' about anything? (Usually, a yellow traingle with a exclamation point in it...) Does it appear to 'see' the HD Audio stuff? Another possibility - I've seen a number of problems where a video card driver installed after the audio driver will 'default' the audio to the HDMI port - usually can be fixed by right clicking on the RT HDaudio tray icon, which gives you access to the sound channel selections...

Just wanted to drop a note - haven't given up on ya - just letting this 'mull through' my subconcious mind for a while; sometimes it comes up with stuff all on its own - actually kind of scary

You're missing a whole tab in your sound manager - the speaker one, of course:

What hasn't occurred to me yet is WTF could possibly cause that, and, obviously, the CODEC itself is being recognized...