Windows XP will not boot to desktop after installing Avast

Hey folks.

I’ve installed Avast Pro on about 10 machines for a company (we’re a reseller) and two of those machines will not boot to the desktop after Avast is installed. The PCs are running Windows XP Professional and they will boot up fine, but after clicking on the username to log in, Windows just freezes. No matter how long I wait, the desktop never comes up. I can get into Safe Mode just fine. If I disable the 4 Avast services and the one startup item using MSConfig, the PC still locks up. If I remove Avast, the PC will boot as normal. These PCs had Windows Live One Care on them (but so did the other 8) and I’ve ran the OneCare removal tool on them both to no avail. Any ideas?

I suggest you uninstall avast in Safe Mode.
Which other applications could be conflicting with avast? Which was your old antivirus (besides OneCare)?

Figured it out. There was an old AntiVirus on the system called eScan Corporate Edition 2006. I didn’t realize it was there because instead of uninstalling it, someone just disabled it in msconfig. It had a password on it that the customer did not know. So, I contacted support at http://www.mwti.net and they directed me to a password reset utility for the software (http://mail3.mwti.net/esreset.com). Then, I was able to remove the product with Add/Remove. Deleted the escan directory and Cleaned the registry with ccleaner. One of the PCs had traces of Norton left on it as well, so SymNRT took care of that.

Normally, Avast will throw a fit when I install on a PC that has another AV software installed. Maybe Avast can be improved to look for not only active AV software, but the leftover traces or disabled AV software that might cause problems like this??

The two PCs are running perfectly now. Avast alongside Malwarebytes Pro. They make a great “malware” tag team.

Thanks for the help. I wanted to post my findings to help others in the future.

Glad you’re ok now Fyrestryke.