Do I have a virus? Avast blocking sites.?

[Alan]

First I'll say Avast is one of the best antiviruses and don't let anyone tell you different. But Avast alone is not enough with todays hacked up internet. You should do a few things that will increase your security and stop the problems. First you should do regular boot time scans with Avast, not the regular scan but look for Avasts boot time scan feature and use it at least 3 times a month. Second find a malware scanner like Malwarebytes, Spybot Search And Destroy, Combofix, Bitdefender etc. Try one, try them all but find one you like and run regular scans with it as well, you will notice that one tool can't find all, and won't do it all, but a combination of a few good tools is great protection and clean up.
Last take your updates seriously, those annoying updates are worth there weight in gold. Your js:Script Trj, might have been prevented if you are 100% up to date with your java version. Google: Java, and update to latest stuff. There's a few addons to Firefox to help limit and control the Java hacks that can go on while on a website, add the NoScript addon to Firefox. Also if you haven't already, do 100% of Windows security updates if your using Windows.........and keep it that way.