I'm really sad to hear that your getting these problems and can only suggest what I would do if I was having the same trouble..
Check all drivers are the latest versions and that means everything from graphics to chipset and obviously sound.
Check system Bios is latest version as this can have a major effect on sound issues.
Check system RAM using something like 'Memtest': Memtest86+ - Advanced Memory Diagnostic Tool (remember to test only one stick at a time)
If the install was an 'upgrade' then back up and perform a clean install.
If all the above fails then please post again and we'll endevour to find the issue.
Check all drivers are the latest versions and that means everything from graphics to chipset and obviously sound.
Check system Bios is latest version as this can have a major effect on sound issues.
Check system RAM using something like 'Memtest': Memtest86+ - Advanced Memory Diagnostic Tool (remember to test only one stick at a time)
If the install was an 'upgrade' then back up and perform a clean install.
If all the above fails then please post again and we'll endevour to find the issue.