Advast blocking all websites

I have had avast on my pc for a while. I used the free version
Then I bought it for a year. Tonight I have been
Using the pc all was fine, now when i try to get into my usual websites
Netmums sky I get the malware avast box pop up. It says threat has been detected. Avast has blocked a harmful webpage or file. I need to get into sky to read my emails. And short of removing avast i dont know what else to do. I doubt there is a virus on sky.com???

 

I just made a similar post - I bypassed the problem by using K-Meleon browser not Firefox - I didn't test IE.