NIS 2009 Question

I don't want to sound like an idiot, but I've had NIS 2009 for only a matter of weeks and now I'm having problems accessing certain websites.  The full scans indicate nothing is wrong. 

 

Isn't the software supposed to identfy spyware/malware/viruses and eliminate them?  

 

The customer service at Symantec was horrendous, not answering any questions directly unless I paid $99.  I have brand new software on a computer that was running fine.

 

I am not receiving any phoney security messages, no blue screen of death, just network timeout or website unavailable on random sites. 

 

Why did I purchase the software if it isn't going to keep these things off my computer - or get rid of them if they infiltrate?  

 

I know nothing of computers except how to use them. Paying for and correctly installing security software should be enough to protect me.  My computer is up-to-date 100%.