No sound, can't update Vista, can't install new programs

Hi,

 

I have been searching the net for 2 weeks and all to no avail!!! Please help...

 

My wife's laptop has no sound (checked the usual Control Panel), Windows Installer is not working, I can't update Vista (error 800401454) and online banking sites show 'There is a problem with this website's security certificate".

 

I have updated Norton and Malawarebytes, run Windows Malcious Software scans and the conficker (or the he other name for it, something worm perhasps) scan from Norton... and nothing has been found. 

 

We have not installed new programs lately or changes any settings on the computer; my wife uses the laptop for web browsing only.

 

Crikes I am getting desperate...

 

SIncere thanks for help!!! Any advice would be much appreciated!

 

 

 

PS I had problems with loading virus programs and updating XP on my laptop a few months ago; conflicker type viruses were found and problems went away when eradicated.