Is Avast being recognized by your Action Security Center?

Have you checked for malware?

Is your machine acting normally?

Here are the download files to v.889 assuming your uninstalled MSE:
Free: http://files.avast.com/iavs5x/setup_av_free.exe
Pro: http://files.avast.com/iavs5x/setup_av_pro.exe
AIS: http://files.avast.com/iavs5x/setup_ais.exe

Let me know how this works for you. Thank you.