Hi,
I have recently ran into some of my clients with rootkit infections. Unfortunately they were not previously using avast! so they got infected. 
However, avast! does not want to seem to detect and remove these rootkit viruses once I put avast! on their machines. I am hoping that you guys can work on the ability to remove infections that are already on the system that you install avast! onto. Since you guys no longer provide the âvirus removerâ program these days, it seems like there should be a bit more focus on removing infections already on the system at the time of avast! installation. I continue to be impressed at avasts ability to stop infections but sometimes detecting and removing infections that were already on the system seems to be an issue. I had to use Hitman Pro to get rid of the rootkits because avast failed. I am confident avast! would have prevented these infections but the installation of avast should include something similar to Hitman Pro to get rid of CURRENT infections at the time of install. I cannot spend my days tediously removing these new infections by hand, itâs just too time consuming. Thanks
So, get install avast before 
Serious, no joking, prevention is better than cure, better safe than sorry⌠avast first.
You can also read the instructions, download and burn (maybe from another computer), finally use one of this rescue CDâs:
You can check also this comparison article.
I usual find avast boot-time scan after install of antivirus sorts all these out. you can load in Safe Mode I think and run boot scan before first boot into Nornal Mode.
But specialist tools may be needed for the rootkits rather than general antivirus. You could also go to gmer http://www.gmer.net/ (Download.EXE) or sophos http://www.sophos.com/products/free-tools/sophos-anti-rootkit.html or other anti-rootkit application to scan for rootkits.
GMER technology is already incorporated into avast! antivirus. Read this.
âGMER is fully integrated and optimized within avast!,â said Przemyslaw Gmerek, founder, GMER.
yes I know. but the specialist tool for specific objective? Whether better outcome is of course arguable.
Yes it is, but the incorporation/optimization is much different to the stand alone GMER anti-rootkit as the idea of the anti-rootkit scan within avast is to take the difficult decisions away from the user and air on the side of caution/safety. It also doesnât produce the vast amount of information that GMER does (which needs to be analysed) in the form of the report.