No Sound after upgrading to Windows 7 from XP SP3 and getting error "We're sorry, but Microsoft Automated...?

No Sound after upgrading to Windows 7 from XP SP3 and getting error "We're sorry, but Microsoft Automated Troubleshooting Services failed to install. Please try again later" while installing FixIt designed to fix this problem!

I upgraded to Windows 7 from XP SP3 and installed Win7 on the same partition without deleting and I installed all the needed applications and all the hardware drivers including motherboard ASUS's and Realtek's, which are designed for Windows 7. Then also, no sound from speakers nor from headphones and evenw microphone is not working. When I click on "test" (after right clicking on speaker icon, playback devices, and speaker device) it says "Failed to play test tone" I have tried the options listed in forum but in no use!

I am also having problem with "Mats_Run.AudioPlayback" as I tried to fix my "no sound from speakers, headphones, or even from the system" what should be done to get audio playback. I have installed all the hardware, applications, and drivers needed, but still no sound whatsoever!

I have plugged in speaker jack to the middle female connector at the back panel. I had connected both my 2.1 speakers and headphone with microphone to a splitter and had inserted to the same jack while using XP. It was working fine, but problem has started only after installing Windows 7. Strangely, the sound was coming while I was listening to an audio file online designed using Adobe Flash, but has stopped.