In the last link I gave you for the ADi..... driver, you said it was for some driver update utility. When I tried it, I got a file called win57991.exe. Is that the same file you downloaded? Since my sound is working properly, I didn't want to run it.
Could you give me a screenshot of the Control Panel\Sound\Playback screen? Make sure that all disabled and disconnected devices are shown. You can do that by just right clicking in the white space on the screen.
I getting pretty close to not knowing where to go next-
You're graphics card supports Directx10.
I still think it's a driver issue. I've seen problems with 3D video depending on whether or not the screen was maximized or minimized, in another forum. My best recommendation is to disable the Xear and install the Realtec AC97 driver. I don't know why your AMD was disconnected. I guess it had something to do with the computer repair.
Do you have any codecs installed like divX or Xvid? If so try to uninstall or reinstall them? Also from the start menu type in dxdiag. Look under the audio and video tabs to see if it finds any problems. Also check undo video that the directx accelerations are enabled.
Your motherboard supports the SoundMax ADI1986A audio codec. Sadly, the download page for your particular motherboard does not feature any audio drivers. However, another ASUS model which uses the same codec does. Try ASUSTeK Computer Inc. -Support- Drivers and Download M2N-MX
4 x 4GB DDR3-1600 Corsair Vengeance CMZ8GX3M2A1600C9B (16GB)
Graphics card(s)
MSI GeForce GTX770 Gaming OC 2GB
Sound Card
Realtek High Definition on board solution (ALC 898)
Monitor(s) Displays
ViewSonic VA1912w Widescreen
Screen Resolution
1440x900
Hard Drives
OCZ Agility 3 120GB SATA III x2 (RAID 0)
Samsung HD501LJ 500GB SATA II x2
Hitachi HDS721010CLA332 1TB SATA II
Iomega 1.5TB Ext USB 2.0
WD 2.0TB Ext USB 3.0