Windows 7/8 no sound (after ubuntu dual boot)

So my brother has a Asus laptop(old) which came with Vista Ult. When Win 7 was released i installed it and everything worked fine (all the drivers). Then my brother tried dual booting it Win7 and Ubuntu (might have been 10.04 or something similar). After the install everything was working fine in Ubuntu, but when he rebooted into Win 7 there was no sound coming out of the speakers (earphones and headset were working fine). In the windows sound 'Playback' settings the speakers would show up set as default, the audio levels would jump when you played a video or sound file, but no actual sound came out of the speakers.

I tried updating drivers, clean(format HDD) Win 7 install with and without the original drivers just the automatic ones that windows picked up on, on separate occasions. After all my attempts sound through the speakers wasn't working in Windows. But when i would load Ubuntu live from USB and sound would work fine.

Later i tried installing Win 8 and the same thing happened, no sound. I even tried installing the original copy of Vista and all the drivers again and the same thing would happen, everything but the speakers would work.

Any ideas to get the speakers working in Windows?

More info 1
-I would would like to add that the bios is up to date and have tried resetting all the bios setting to manufacturer default.
-As i have 2 of the laptops(my brother and I) i have also tried swapping the HDD's and the same result.
-In safe mode the sound icon has an 'X' through it, 'No audio devices are installed'. The troubleshoot results are 'One or more audio service isn't running --- Not fixed'

More info 2
-I actually got the sound working once not sure which OS Win7 i think, by just swapping the OS between Vista and Win7 few times and installing the drivers... But then i tried to do a clean install and speakers stopped working again. I was never able to replicate the results again (not exactly sure what made it work).

Solution 1:

I have exactly the same problem with my Samsung QX410. After reinstalling Windows, then logging into Fedora, then back into Windows I discovered again the problem which was the cause of reinstalling. Fortunately I found a solution at quora and it works for me: just turn the Windows to sleep and then wake it up (at least the procedure is faster than reinstall or shutdown).