Please help: Windows automatically blocks avast upon startup

[minerva]

I've loved Avast and I've had no problems until yesterday... I hope someone can help me!

When I start my computer, I receive an error message at the bottom of the screen that reads in part "Windows has blocked some startup programs..." when I click on the message, Avast has been blocked and I have to manually start it by manually granting UAC permission.  This is weird because yesterday when I was looking at my registry entries, I could have sworn that Avast was on the allowed lists.  This has not happened before.

I uninstalled avast and reinstalled as admin (I may not have done it correctly the first time).

OS: Vista
I always use Firefox.

I'm not sure but may have had the same issue with Malwarebytes and Adaware.  I installed yesterday and then uninstalled thinking there may have been some weird conflict but that didn't resolve my problem.  I plan on reinstalling Malwarebytes.

I happened to run into a virus yesterday... popup window with Av8Scan, I clicked on it thinking it was real but apparently nothing downloaded because I got some sort of popup to that effect (Avast was running at time).  Malwarebytes and Adaware didn't find anything and I didn't find the normal Av8Scan reg keys when I took a quick look, so it may not be caused by a virus/spyware etc.

I'm stumped and don't know what to do.  I keep wondering if I did something weird when I tried to go into safe mode yesterday or was checking my reg keys but I thought I did OK. 

I'd be so grateful if someone could help.  I'm sinking here!  I think there's something bad happening and I have no idea what.

[SafeSurf]

Hello minerva and welcome to the forum.

First, I would uninstall ad-aware since this is an obsolete program that has now been replaced with better definitions with Malwarebytes (MBAM).  Upon uninstalling, use the vendor's uninstaller tool, then reboot your machine.

After this, use a cleaner like CCleaner, freeware system optimization, privacy and cleaning tool.  There is a Slim version available as well at http://www.piriform.com/ccleaner/builds – 4th option down.  It removes unused files (cache, temporary Internet files, etc.) from your system, allowing Windows to run faster and freeing up valuable hard disk space.  It also cleans traces of your online activities such as your Internet history.  Additionally it contains a fully featured registry cleaner (make a backup in Documents as a just in case).  Reboot. 

Next, reinstall MBAM http://www.malwarebytes.org/, make sure you update both the program to 1.50.1.1100 and update the definitions.  You need to update the definitions prior to scanning every time.  Run a full scan (in the future you can run a quick scan) and make sure you put any infections into quarantine.  Report back with a cut and paste your MBAM report from the log tab of MBAM so we can analyze.

When you did your uninstall/reinstall of Avast the other day, did you use the Avast uninstaller tool http://www.avast.com/uninstall-utility?

What firewall do you use and does it allow Avast permission to access?

Please let report back with your MBAM log and let us know if any of the above helps fix your problems.  Thank you.

[minerva]

Dear Safesurf,

Thank for all of the advice... it's taken me a few days to do everything given work and houseguests.  Fabulous instructions, by the way.  I could follow it all and clearly this isn't my lingua franca.

I did everything you asked and a couple more things.  Finally had the courage to use the CCleaner and deleted tons of stuff. Installed Revo and cleaned out additional files.  MBAM log came back clean, as did Avast scan.

The error message I've received is "Windows blocks programs that need permission to run...."  Maybe this is a Vista issue rather than a virus/malware?  Of course, Avast appears on the Windows Defender list as permitted (and I went in and manually gave Avast the highest permissions just to be sure) so it doesn't make sense why I have to _also_ manually permit Avast to run every time my computer reboots.

I did an end run around the error message by going to task scheduler and starting Avast upon login (not startup).  Now it is running automatically again when I reboot.

However, in addition to the running version of Avast, I'm still receiving the Windows error message telling me that Windows is blocking the program.  I have to click allow even when the program is already running in order for the error box to go away.  And Avast wouldn't let me change/delete the Avast registry key that is still causing the problems.  Any suggestions for how to get fix this so I can avoid the annoying error messages?

My firewall is Windows Firewall.

Thank you!

[marc-d-l]

What happens when you shut windows defender off? does it still show error?

[minerva]

Hi Marc,

Good question .  I get error message whether Windows Defender is on or off.  And Windows Defender clearly states that Avast is allowed. 

-M