Hello,
I have problems with Windows 7 and Avast Free.
First, I believe I ran into something nasty off of that darn internet. So, I’m trying to use Avast to sniff it out.
Now I cannot logon to my PC. There are no user accounts shown on the welcome screen. But, I can logon in Safe Mode (user accounts are visible). But, I cannot get Avast to run in Safe Mode.
So, I’m trying to schedule a boot-time scan using the command prompt. Instructions are to type >sched /A:* (these came from Avast help page).
When I do this, sched gives me the following error message:
Cannot load main engine (2)!
Any suggestions of what to try next? Thank you!
Hi, nevermind, problem solved. After sifting through dozens of posts (elsewhere) about the empty welcome screen minus all user accounts (but the safe mode showing them just fine) and the fact that system repair was no solution and neither was system restore, I opted to uncheck all the non-Microsoft services and startup items in msconfig. I didn’t hold out much hope, but another frustrated windows user with very similar experience said this was his ultimate answer. And behold, so it is with me. The user accounts re-appeared and I was able to logon with pretty much everything in msconfig disabled.
Then I began a process of re-enabling services and startup items, one at a time, checking that I was still able to boot successfully. I should mention that I did NOT enable a few services from Adobe since the other windows user I was following did painstakingly determine that it was an Adobe service (or something called an Adobe service) that was causing the trouble all along.
Now it gets a little more interesting. Avast would not enable in msconfig. Although I tried, the checkboxes were mysteriously cleared after boot and no Avast icon was down in the system tray. I manually double clicked my desktop icon to start the program, and after a long delay, it did finally start. I asked it to enable a boot time scan and it claimed to do this. But, a reboot proved it wrong as no scan took place. I was never able to auto-enabled Avast in msconfig. I attempted to uninstall the program altogether and, since it asked nicely, opted to give it one more chance and updated and repaired instead. Once again, I had to manually start it and it again could not enable the boot time scan. Then, but ONLY through a command window, was I finally able to successfully enable a boot time scan (sched /A:*). So, after one more reboot, the scan took place. But, it did NOT find anything. Crazy.
So, now all the prior services and startup items were enabled (except for Adobe) but, Avast was reluctant. I did a full uninstall next. And, reinstalled the latest version from Avast.com whereupon it is now enabled (checkboxes checked) in msconfig. And, all seems well.
No idea really what the root cause was. Some kind of weird interaction between Avast, probably the registry, some type of service from Adobe (maybe), and one of those “funny” websites.
stay away from those “funny” websites. 
WOT can help with that. See my signature below. (Caveat: Reputation-based rating system, so ratings are a guide.)