I recently updated my PC from Windows 7 to Windows 8, and was surprised to see that the update went quite smoothly. There were no glitches, and Windows Update Assistant was honest enough to tell me upfront which programs would work, and which would not. Finally, after a long and painful hour-long process, my PC was ready with Windows 8 pro, and it felt good that nothing ended up broken in the process. However, my happiness was short-lived and I found that none of the tiles was working under Windows 8. When I click on a tile, it simply flashes the tile, but no application launches after that.
A quick search revealed that the problem was not with Windows 8, but with Avast Antivirus. Now, many people have had the same problem, and they have removed Avast Antivirus altogether to fix this issue. I use Avast Antivirus because it offers the best free protection available out there. It has a high detection rate, reports fewer false positives, and is good at removal too. Its low memory footprint makes its presence less intrusive, and overall, it is perhaps the best free antivirus. Removing Avast was not an option.
The solution is not in removing Avast, but in updating the program. Head over to the update program section on the Avast dashboard (Maintenance -> Update), and perform a program update. Once the update is done, you will be asked to restart your system.
On a successful restart, your Avast antivirus will show that it is updated completely.