I always use avast, but when I get this problem I switch to kaspersky trial.
Your MBAM scan came out clean...good news.
Do you currently have Kaspersky trial on your machine now along with Avast? If so, having 2 AV's (antivirus software) on your machine will cause conflicts. You will need to run the
Kaspersky (KAV/KIS) Uninstaller Tool:
http://support.kasperskyamericas.com/knowledge-base-article/1464, then
reboot your machine.
After this, since having 2 AV's most likely corrupted Avast, you will also need to uninstall Avast and do a clean install:
1. Save a copy of Avast for the product you need and save it to your HDD:
http://www.avast.com/download-software – all products (Free, Pro, AIS) – 6.0.1091
or you can try the beta version 6.0.1119:
Free:
http://files.avast.com/files/beta/6.0.1119/setup_av_free.exePro:
http://files.avast.com/files/beta/6.0.1119/setup_av_pro.exeAIS:
http://files.avast.com/files/beta/6.0.1119/setup_ais.exe2. Download the Avast Uninstall Utility
http://files.avast.com/files/eng/aswclear6.exe and save it to your HDD.
3. Disconnect from the Internet at this time.
4. Go to Control Panel and uninstall Avast through Add/Remove Programs if possible and reboot.
5. If Step 4 fails, boot into
Safe Mode (hit F8 repeatedly) and run the Avast Uninstall Tool.
6.
Reboot.
7. Install the newest version of Avast and
reboot.
8. Get Internet access and register your copy or add the license key for Free, Pro, or AIS.
9. Update the Avast definitions.
Let us know if this fixes your problems. Thank you.