Avast anti-rootkit

Can I use Avast anti-rootkit without any harm, although I have Avast Antivirus free installed? I just ran a custom scan with a setting “rootkit scan quick” (not sure about the exact words).

I think the old avast anti rootkit is outdated an now integrated in avast AV
http://forum.avast.com/index.php?topic=41836.0

This is the one used now http://public.avast.com/~gmerek/aswMBR.htm

Is it enough to run the quick rootkit scan or do I have to run the deep scan?

Well I don’t know why it is that you think you need to run a rootkit scan ?

Avast does a rootkit scan 8 minutes after boot, so essentially it is doing one every day or however many times you switch your computer on.