Windows 7 Ultimate x64, Multiple Problems

MSE and Avast have been the two most recommended freeware AV's here for years.

I give the edge to MSE if only because it's less intrusive with registration and the annoying gadgets which have to be deselected during Custom install or repair.

I notice that recently MSE has been recommended more frequently.

Both can have their issues although they are normally fixable, but if not they can be interchanged.

These tests are always all over the place, often influenced by their sponsors.

In spite of lower ratings in many tests MSE and Avast have remained most recommended here for performance reasons. This is why we also heavily recommend Malwarebytes for routine scanning or it's paid Real Time protection for those prone to infection.

There are other good paid AV's like ESET, Bitdefender, Kapersky, Avira which don't compromise performance like the more bloated ones, which unfortunately come preinstalled on most new PC's and should be treated like an infection themselves.

Bickering in regard to which is the better Antivirus when you have serious issues is just being plain puerile.
If you have tried to update to the current version of Avast v.7 from v.6, this maybe the cause of the video files server execution failing as there are serious issues with the Avast v.7.
Shame on the Avast developers to make v.7 public.

Quote (Avast Developer) The problem happened because an invalid definition file was uploaded to our server, and was being sent out to clients.

Sometimes when IE won't open the winsock has been corrupted.
Try running the following commands.

1. Open up the command line utility and enter:
netsh winsock reset catalog (resets winsock entries)
netsh int ip reset reset.log hit (resets TCP/IP stack)
2. Reboot your PC