My Acer Extensa, Windows Vista, Lost Sound

Been here for the last few days with this ''lost Sound'' problem.
Tried all suggested methods but in vain.
Finally got this notification
''Windows Driver Foundation - User Mode Driver Framework Host
Process stopped working and was closed.''
That means my pc cannot be installed with a Sound Driver !

Tried to Back Up files and got this message: ''Back Up cannot be done.
Class not Registered (0X80040154).

Please tell me what I should do now. Thank you.

Also tell me : (1) how to go to Factory Default,
(2) what steps to open Windows again

Or, is there any possibility for you to take over control and fix the error by remote.
Am a old male and have looked at girly pictures. Beyond that me have nothing to hide.
Thanks and Cheers.