Static noise?? Script errors??

I have had issues with my sound since SP2 install.  Now instead of the usual dings and other alert noises I get a static noise.  Sometimes it's machine gun static.  What is the cause of this? 

 

Secondly, when I am on websites I get an awful lot of script errors.  Is there a way to overcome this?  I am not the most computer proficient, but I have had this computer for over 3 years and yet to have a crash, so I must be doing something right.  So if you can tell me what to do, I'll listen.

 

I have a Dell 8100.  Any information would be appreciated.